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Chevy Drag Racing - Watch The Details

Performance Q&A

Kevin McClelland Jul 1, 2006
0607_chpp_01_z Drag_racing Carburetor 2/1

Here in Northern California we have beautiful Infineon Raceway, which many of you have seen on TV while watching either the NASCAR road race or the NHRA Autolite Nationals. However, for us local drag racers who need our monthly fix of speed and competition, we get the short end of the stick; the Road Course gets most of the dates, and the Russell Racing School has its road-racing instruction here. That said, we'll take the track just about anytime they'll let us have it. The drawback is that it gets rather cold around here in January and February, which leads me to this month's title.

I race my Super Gas Don Davis roadster in the Summit ET series in Super Pro. When I bracket race the car, I run it wide open with no throttle stop and it runs 8.90s at 148 mph. With the track being somewhat traction-limited from of the cold, it helps me get down the tarmac without driving 1,400 feet in the quarter-mile! Well, last weekend we had our second points meet, and on my first time run the temperature was a brisk 43 degrees. By mid-afternoon we had a high of 58 degrees. Needless to say, if you get out of the groove at all, you're driving the car. By the time we got through six rounds and I was in the final, it had once again gotten colder, and what little sun we had went behind the main grandstand. Unfortunately, at about the 330-foot mark it started spinning the tires and I missed my dial by about 0.02 second, handing me the loss. Ex-Super Gas World Champion Dan DiVita is our chief starter for these races and gets to watch all of us try to get down the track. After the final he said to me that the back of my car was too stiff. Well, I've adjusted my shocks over the years based on the power output of my engines and the track conditions. However, I've never run the car that much at full power. When the car is on the throttle stop and competiting in Super Gas class, I run the compression on the shocks as loose as possible. If I run them any looser, it'll actually draw the suspension up into the car when I close the throttle on the stop and spin the tires slightly, making it inconsistent. Well, running the car at full power I never see this transition. I'm sure I can soften it up a few more clicks. Just slight changes like this can take you from the winner's circle and make you a first round duck. Watch the little details!

Father-Son Battle
Q My father and I are restoring a '65 Nova. We have a Heidt's Mustang II frontend with disk brakes and drop spindles, and a Moser rearend with 3.73:1 gears, and we haven't decided whether to use a TH400 or a 700-R4 trans. My father is stuck in the old school and wants to build a 396. I told him we should build, at minimum, a 427 or a 496. I cannot find any good combinations on 396s and he would like to get over 500 streetable horsepower.
Jon Albonico
Via e-mail

A Jon, sometimes you should really listen to your father. There are years there you have yet to cover. Maybe he wants a 396 for other reasons than just old school-maybe he wants to limit the power of your first project.

Getting to your question, yes, it would be much easier to reach your 500hp bogy with the larger-displacement engine. Also, good 396 cores are becoming harder to find, and it will cost you the same money to build the 396 as it would be to build, let's say, a 454. For that reason alone, you should build the 454. You will be working the 396 much harder to build 500 hp. On a 496, you are just asking for 1 hp per cubic inch. With the 396, you will need 1.26 hp per cube. That is quite easy to reach with a small-block; however, with the weight of a big-block's rotating assembly and the port size of the cylinder heads, it can be rather tricky reaching that power with good street manners. You'll need a camshaft that comes in around 240 degrees duration at 0.050 tappet lift, rectangle-port heads (preferably aluminum), and a single-plane intake that will let the engine make good power in the 6,500-6,800 rpm range. The torque will suffer with the package, but you should make your horsepower.

As I was saying before, I would recommend going for the cubes unless your dad is trying to hold back the power. Are you sure he's the one that wants the 500 streetable horsepower?

Vetted BoxQ I have a TH700-R4 trans from an '88 Vette that I want to swap into my '84 Camaro Z28.The engine is a noncomputerized 350 cid. What, if anything, can I do to make the speedo work? I believe the Vette speedo was electronic. What about the rear mount and torque arm? Are they bolt-in? Do I need a new tailhousing or a conversion kit of some kind? Dean MartinOliver, BC, Canada

A A Vette trans swap into your Camaro is great. The Vette trans has a larger Second-gear servo for increased Second gear durability, a special valvebody which allows for WOT 3-4 gear changes, and higher line pressure for better durability and firmer shifts.

No, the Vette tailhousing does not have the Camaro torque arm mounting flange. It's a very easy four-bolt swap to install the Camaro tailhousing; the length is exactly the same. As for your speedo, yes, the Corvette had an electronic speedo. It had a signal generator that was driven just like a speedo gear for your Camaro. You just need to swap out your stock Camaro tailhousing with the speedo-driven gear and housing and install it. We would also take the drive gear from your Camaro trans and swap it in to the Vette trans. As for the trans mount, the Vette trans usually has the holes in the case, but they are not tapped. It's a very simple job to tap them out to either 10 mm metric or 71/416 USS thread. Good luck with your swap.

EFI NovaQ I have a '64 Chevy II which I have been working on for about a year. It has a Gear Vendors TH400, a Strange S60 rear with 4.33:1 gears, a Competition Engineering Mini Tub, and a TCI front subframe, plus all the other standard goodies that make American Muscle fun to drive. I am looking at the Ram Jet 502 as a powerplant. I really like the idea of fuel injection but am concerned that this engine is at its peak performance. I haven't seen any articles on upgrading or tuning this engine past the advertised 502 hp. Any info will be greatly appreciated.Jeff MortonSt. Petersburg, FL

A I've dyno'd several of the Ram Jet 502s, and its advertised power output is slightly optimistic. You haven't seen many articles on hopping up these engines because of the MEFI 4 controller. This is the controller for the fuel injection and it is a flash-only programmer. You must have GM proprietary software and hardware to tune it. Being that it is a speed-density EFI system, you have a very small window to hop it up.

Now, the ZZ502 engine is a very good foundation to start your engine combination. Many aftermarket EFI systems give you the tuning ability and flexibility to make major changes in the engine's personality.

Edelbrock offers its Performer RPM Pro-Flo EFI system (PN 3550). This is a complete EFI system from the inlet manifold to the very last sensor and wiring harness. The manifold is a single-plane Victor Jr. oval-port manifold, and a 1,000-cfm four-barrel air valve that gives you horsepower headroom up to 625 hp! Edelbrock has dyno'd this system on a ZZ502 engine with its Performer RPM big-block camshaft installed, and it produced 547 hp. One of the system's best features is the Calibration Module, which allows tuning without a laptop computer. For more information, call Edelbrock at 800.416.8628, or go online at

This EFI system should round out your really trick Chevy II. Good luck with your project and send us pictures for CHP Rides when you're done.

Torquey 283Q I'm building a 283 small-block for my S-10 pickup. It's a basic rebuild with a stock crank, stock rods, and 0.040-inch-over cast pistons. What type of heads do you suggest? I was looking at the World Products S/R Torquer, but I was told that the big 2.02/1.60 valves are not meant for the small bore of the 283. Is this true? They also say that the heads don't come with guide plates and they have to be machined to the thickness of the guide plate to be used. I have a set of Comp Cams 1.6:1 roller rockers I'd like to use, but without machine work, will I have to go with self-aligning rockers? This is just a street engine I would like to run on pump gas. Darren BurtVia e-mail

A With the price of gas comes the fuel-conscience engine buildups: The smaller the engine, the less fuel and air for each stroke.

In short, yes, you would have a problem with standard World Products S/R Torquers. But don't fret; they have something available specifically for your application. World realized the popular S/R Torquers wouldn't work with the small bore of the 305 small-block. The standard bore comes in at 3.740 and World built an S/R Torquer 305 (PN 42650-1), which features 58cc chambers, 171cc inlet ports, and 1.94/1.50-inch valves. If you order the assembled head, it comes with springs for hydraulic flat-tappet camshafts with a max lift range of 0.560 inch. With the smaller combustion chambers and the smaller valve size, they fit nicely in your 0.040-over 283 bore size, which comes in at 3.915 inches. You're right that the heads don't come with guide plates. However, it would be much cheaper to have the rocker-stud pedestals machined down to the thickness of the guide plate than buy new self-aligning roller rockers.

With the redesigned combustion chambers in these heads, World recommends using 350 head gaskets. If you haven't decked the block, which brings the pistons up to zero deck, we would recommend going with GM head gasket PN 10105117. This gasket is 0.026 inch thick and has a bore size of 4.100 inches. Many of the aftermarket gaskets come in at a large 4.166 inches and would be quite oversized for your 283 bore. For more information, contact World Products at 810.939.9628, or online at

Inches Of What?Q I have a question concerning how carburetor cfm ratings are calculated and whether the ratings advertised are accurate. Are they calculated using the same standards as cylinder head figures, like 28 inches of water at X amount of valve lift? I have always been told that straight-leg booster carbs flow more than the down-leg boosters, which flow more than annular boosters, yet they are all rated with the same cfm. The butterfly diameters and venturi sizes I assume are the same. I have never seen anybody actually put a carb on a flow bench and measure cfm. I bracket race and I think this info would help your readers choose the right carb the first time. This is not a transbrake car. I use a pneumatic cylinder via a delay box to actuate the throttle.Tyler MurdockHenagar, AL

A We've all used different systems when we couldn't afford a transbrake transmission. Back in the late '80s I used a throttle-stop timer with a small taillight bulb strapped to the top of my steering column. When the top bulb on the tree would come on I would release a button that started the timer. When the light on the steering column came on I would stand on the gas! It took me about a year to perfect this combination, but one day at I had three perfect lights, and in 1991 I won the TNN/ Centerline ET finals! Later I used the same setup you're running on my El Camino to race Big Bucks Bracket races when I didn't have a race car running.

Carburetor cfm ratings are generated by flowing them at a specific level of vacuum in inches of mercury. Holley and most carburetor companies rate their four-barrel carbs at 1.5 inches of mercury. For one- and two-barrel carbs, 3 inches of mercury. To give you some idea comparing this to cylinder head flow-testing, if you convert 1.5 inches of mercury to inches of water, you get 20.43 inches of water. And the 3 inches of mercury is 40.86 inches. When Holley rates its carburetors, they're tested on a wet flow bench. If you only run them on a dry flow bench, the flow would be much greater without the fuel being added into the air stream. If you take a performance air/fuel ratio of 12.5:1 and break it down into percentages, 8 percent of the total flow is fuel. It would be very safe to say that if you flowed a carburetor on a dry flow bench like a SuperFlow SF600 flow bench, you would realize at least an 8-percent increase in flow over the factory rating. Now, this brings us to another factor in trying to flow carburetors. My SF600 flow bench is rated at 600 cfm at 28 inches of water-this is if you feed it with 230 volts of electricity. Our building only has PG&E's finest of 208 volts on a good day. When all the welders fire up their torches and the robots are humming, my voltage suffers! What I'm trying to say is my bench probably pulls around 550 cfm. If you throw a 750 Holley on the bench you wouldn't be able to pull it up to test pressure. We've seen people block off three of the four barrels and flow them one at a time. This isn't bad, but you really need all four barrels flowing at the same time.

As for booster design, I prefer the down-leg boosters on the 4150 carbs and the straight-type boosters on the Dominators. What sets the flow with the different boosters is the diameter and at what height they are set in relationship to the choke point of the venturi. The down-leg boosters and the straight boosters both reach the same point in the venturi choke point, but with annular boosters it's a whole other story. The booster is much larger in diameter, but there is much more airflow through the center of the booster. Hope this has answered your carb questions. Good luck bracket racing your big-block Impala!

Which Heads?Q I'm building a 377 for my '83 Camaro. The car sports a manual T5 with 3.42:1 gears (will be changed to 4.10s later on) and a posi. It also has open twin 211/42-inch exhaust and headers. The engine is a destroked 400 small-block with hypereutectic pistons and 10.7:1 compression with 64cc heads. I run 95-octane fuel or even 99-octane (both standard in Sweden). I currently have a Comp Cams Magnum 280H camshaft with 1.6:1 roller rockers and a Performer RPM intake. I want to run the engine to about 7,000-7,500 rpm. (Nothing sweeter than a high-revving small-block!)

My problem is that I'm not sure about what heads to use. I've been looking at the AFR 210s and 195s. I'm also looking at the Canfield 220s. I would also appreciate any ideas on carbs. I'm going to use the car mostly as a weekend warrior. Have you guys ever made a 377 buildup?Aron HolmbergStockholm, Sweden

A Aron, you must have a lot of fun over there with your Camaro. What's up with 95- to 99-octane pump gas? Here in California we only get to drink 91 and it doesn't taste very good. We're jealous!

The 377 engine combination is a good mix of the 400 small-block and the standard stroke of the 350. Yes, the larger cylinder bores will allow the engine to breathe well with your choice of cylinder heads. Over the years there have been many buildups of this engine combo. However, with the availability of aftermarket blocks and crankshafts at reasonable prices, it doesn't make much sense to not stretch the displacement out to the full 400 or more. Yes, the 377 revs nicely, but that doesn't make up for the loss in power over the inches.

You have chosen some really good cylinder heads. You can't go wrong with either of the AFR heads. The larger-inlet 210s will push the rpm range higher at the expense of some slow-speed torque. It may be the right direction for you to go to make your T5 five-speed live behind your engine. We've also used the 220 Canfields with great success on a bracket 350. That engine with a 240/250 at 0.050 mechanical flat-tappet cam pushes a 2,400-pound Datsun 240Z into the low 10s at over 130 mph! For the rpm range you're looking for, we would suggest going with a single-plane intake like the Edelbrock Victor Jr. (PN 2903). This Victor Jr. is cast 1 inch taller to add plenum volume and is CNC-port matched, which will line up nicely with either cylinder heads. Check with Edelbrock for more information at 800.416.8628, or at As for a carb, the old standby 4779 Holley 750-cfm double-pumper will work well, with a good balance between drivability and high-rpm performance. You could go with a larger cfm (800 to 850) if you're just looking for all-out high-rpm horsepower.

Lastly, your 280H Comp Cams hydraulic camshaft is going to run out of air long before 7,000-plus rpm. If you really want to reach these engine speeds, we would recommend going with a mechanical flat-tappet camshaft. It's also going to need more duration and lift to let those killer cylinder heads breathe. Check with Comp Cams about the Xtreme Energy XS282S. This camshaft specs out at 244/252 degrees duration at 0.050 inch tappet lift, it has 0.520/0.540 inch max lift, and is ground on 110 centers. Combine this with your 1.6:1 roller rockers and you will have 0.555/0.576 inch max lift respectively. You will also realize a 2- to 3-degree increase in duration. Check or call 800.999.0853.

With this combination, you will have one stout small-block pushing 475 to 500 hp and drinking up some of that really killer high-test you have for fuel. Have fun out in the countryside!

IMP ExhaustQ It's time for a new exhaust system for my '62 Impala SS. The 327 is mostly stock with a 500-cfm AFB with a '65 Corvette cast-iron manifold and a mild camshaft. I have a set of Rams Horn 211/42-inch manifolds and stock head pipes, both of which are new. I plan to use 50 Series Delta Flow Flowmasters with 211/44-inch tailpipes. This car is a cruiser and daily driver. Will this setup have any effect on the low end or economy?Jerry WillardVia e-mail

A You didn't mention what type of system you have on the car now. The factory exhaust, single especially, and also the stock duals are quite restrictive. From the factory system you should expect an increase in part-throttle torque and fuel economy with a set of Delta Flow 50 Series mufflers. A 211/44-inch dual system would be a good balance for your 327 powerplant. If you're looking for a full 211/42-inch mandrel-bent system check out the Flowmaster's American Thunder Header Back Pipe Kit.

Flowmaster offers a header-back dual-exhaust system that utilizes either our Delta 40 Series, Delta 50 Series, or Hushpower II mufflers. This pipe kit is sold under PN 17413 without mufflers and allows you a choice of the three muffler models to fit your taste in sound. The pipe kit comes complete with custom hangers to go to factory bolt holes in the frame for a direct fit. The system fits '59-64 Impalas and has tips that exit right before the rear tires. The lowrider crowd prefers this setup for their extremely dropped vehicles. For owners who want a factory outlet location, Flowmaster has also released a tailpipe kit (PN 1055) that connects to the header-back pipe kit and the exhaust exits at the rear fender line. The system is a full 211/42-inch mandrel-bent kit.

So for you 348/409 owners-or those guys that just can't get enough and have slapped a sweet big-block between the framerails-Flowmaster has a killer exhaust for these cars. You can check it out at 800.544.4761 or online at

Sock MonkeyQ I have a '77 Chevy Stepside K10 truck with dual tanks and I've been having a fuel delivery issue. I replaced all the visible filters and pump, as well as the power valve in my Holley. I'm still having problems with it not idling, and it sputters under throttle. Did the '77 come with an in-tank filter? I did not start having problems until I was four-wheeling and slid sideways; ever since I've had problems at low speeds. Freeway driving is still OK, but I go through a lot of fuel, more than usual. Mike HughesVia e-mail

A To answer your question, yes, there are filter socks attached to the end of the pick-up tube in your tanks. However, I don't think this is your problem. You say this is an idle and stumble problem and the engine runs fine on the freeway. There is a much higher fuel flow demand on the fuel system during freeway driving.

You also said you have replaced the power valve in your Holley carb. Was this because of an overly rich condition? Now, the carb may be maladjusted if the previous owner had it set to a poor-condition power valve. Or you may just need a full carb rebuild. The idle air bleeds in the main body of the carb are rather small and can pick up trash. If the idle or main air bleeds are plugged or restricted it will cause the carb to run rich. This may help explain your fuel consumption problems. Either pick up a Holley Strip Kit for your model carb or send your carb off to Sean Murphy at SMI. Sean is a Q-jet specialist, but he has many years tweaking Holleys. You can reach Sean at 714.842.1881 or online at

Not Worth The DrillQ I am rollerizing a small-block 400, complete with Vortec heads, just like your recent buildup. I have a perfectly good Edelbrock Performer sitting on the mill in my '76 Vette. I have heard of guys machining the bolt holes to use regular intakes on the Vortecs. Do you have an opinion on this? If I port-match them, is this a viable low-buck solution? Or am I asking for hassles and performance loss? Thanks.Gary LacoursiereWinnipeg, MB, Canada

A Why do you think we put this book out every month? It's just so guys and gals like you can steal our ideas. Hopefully, we come up with pertinent information to feed your performance habit. Yes, used Performer manifolds are a dime a dozen out there. However, the unique vertical bolt pattern of the Vortec cylinder heads, with their plastic reinforced silicon intake gaskets, seal up very nicely. Sure, some people out in the field and aftermarket parts suppliers have redrilled the Vortec heads to take the standard Gen I small-block manifolds. What I don't trust is bolt holes that are adjacent the coolant passages in the heads. When you drill the original early bolt pattern, you somewhat cut into the standard Vortec pattern, and there is very little sealing surface around the coolant passages. I think it would be money well spent for the proper Vortec Performer and a long way toward peace of mind that the coolant is going to stay in the cooling system, not in the oil pan! Pick up a Vortec Performer from Edelbrock under PN 2116. For more information contact Edelbrock at 800.416.8628, or online at

Timing's EverythingQ I have a '64 Chevelle with a 327 and a four-speed. I just rebuilt the 327 with 0.030-over flat-tops and a polished and balanced steel crank. The top end is a set of 462 heads with 1.94/1.60-inch valves with a bowl blend. I used a complete Comp Cams XE268 kit and an Edelbrock RPM intake with a 1406 Edelbrock Performer carb. The ignition is a MSD Pro Billet HEI. I am trying to set the timing, but I'm having problems. I have the timing at about 18 degrees BTDC. It doesn't seem to have a lot of acceleration. The compression ratio is 9.5:1. The car does not have headers, but it does have 211/42-inch dual exhaust. The Flowmasters sound like glasspacks at about 2,600 rpm. Would an X-pipe help the sound above 2,600 rpm? The car also has 3.08:1 gears, with a M21 trans. I am not sure how far to go with the timing. Thanks.Ryan BlevinsYakima, WA

A Your Chevelle should have some snap in the throttle response, and your package should give you good performance. We need to start talking total timing, not initial. But first I would like to talk about cam timing. Did you degree the camshaft when you installed it? With 18 degrees of initial, the engine should have good performance and throttle response. The XE268 Comp Cams is a good size camshaft for your 327, and the 462 cylinder heads were the mainstay of performance through the '60s and '70s. If the camshaft was installed a tooth retarded, or the cam or crank gear was machined incorrectly, this would really hurt the performance of your engine. Check on Comp's Web site for instructions to degree the cam. The XE line of camshafts are ground with 110 separation angle, and the intake centerline was ground with 4 degrees advance. This puts the intake lobe in at 106 degrees ATDC. I would recommend checking this out first before spending any money on new components. As for spark advance, your 327 engine buildup will want between 34 to 36 degrees total timing that is all in by around 3,200 rpm. From there you can see where your initial timing falls. You may need to limit the amount of mechanical advance to get the initial timing in a range you like. An initial timing of 18 degrees will give you great throttle response and slow-speed performance. If you run your Chevelle on super unleaded (91 here in California!), you should have no problem with these timing specs.

You said that you have a very unpleasant (glasspack) exhaust note. This leads me to believe that the camshaft may be retarded. No, I don't think an X-pipe will give you better sound. Also, you said you have stock exhaust manifolds. If you went to four-tube headers, you would gain around 20 to 30 lb-ft of torque, below torque peak. It's just a thought. Good luck.

C-Clip SafetyQ I have a '72 Chevy Nova with a 468ci big-block and a TH350 trans. The rearend is the factory 8.5-inch 10-bolt with Richmond gears and an Auburn posi. I also have Slide-A-Link traction bars, monoleaf springs, and factory C-clip axles. The car runs consistent 7.40s in the eighth-mile and I have been able to run a best of 7.06-only I have never been able to do that since!

While I'm pleased with the way the car runs, I want to go quicker. My concern is the stock C-clip axles being the weak link. When I originally started the project, the idea was for a street/strip machine. After burning up multiple transmissions driving the car around town, and getting tickets for the loud exhaust, I have decided that driving it on the street is not an option. Needless to say, the car and I are much happier now.

If I change to hardened axles, will the rest of the rearend take the abuse of drag racing? And how hard would it be to change it over to a 9-inch Ford? I read somewhere that a 9-inch out of a '69 Cougar is almost a direct bolt-in. Is this true? I happen to have one and the dimensions look like it will fit, but the spring perch is a little different. Another concern is the emergency brake cable. Will the Nova cable work or is there another aftermarket setup out there? Are there any other issues that I need to be aware of to do this swap?Clifford ArnettBlooming Grove, TX

A That is one running Nova. If you convert the eighth-mile time into quarter-mile, you're running in the 11.40s, and your quick run puts you at a 10.88! That's hauling the mail for your little street Nova. We would be much happier, as would the NHRA tech department, if you would get those stock axles out of your car.

As you have probably read in our mag and many others, the 8.5 corporate rearend is very strong and many a drag car has run in the 8s with one that's been properly prepared. Yes, you will need C-clip eliminators and aftermarket axles. We would also add an aluminum rear cover with load pins to reinforce the rear axle main caps. To finish off the hop-up, we would install a tubular support that connects the two axle tubes with a brace across the back of the housing. This prevents the axle tubes from tweaking forward and putting undue stress on the axles. Your Richmond gears and Auburn posi should keep up with the rest of the package. You can pick up all the above-listed components from Strange Engineering, which offers a complete line of parts for the 8.5. And when you want to dump the posi, Strange has both aluminum and steel spools to replace it. Strange's Pro Race Hy-Tuf axles are sold under PN A1000, the C-clip eliminator kit under PN A1030, the Aluminum Rear Cover under PN R5201, and call for the rear brace kit. This will give you a very strong 10-bolt diff. If you are going to foot-brake the car and stay away from transmission brakes, this should give you years of trouble-free service. Give Strange a call at 847.663.1710 or check online at

As for your 9-inch rearend, yes, the Cougar rearend is almost a direct bolt-in. The width is perfect, but we would cut off the spring perches and set it up with 1.5 to 2 degrees of positive downward pinion angle With the Cougar rearend you end up with a stock Ford rear-end. These axles are equipped with 28-spline axles. You would need all the components that you have above and more. It's a coin toss which one would cost more. Yes, ultimately, the 9-inch would be a stronger rearend. However, to build it bulletproof, you would still need an aftermarket third member, gears, spool, axles, and back brace. Unless you're going to put a much more powerful engine or a transbrake (which would kill your TH350 trans) I'd stick with your 8.5. Good luck!

If you have technical questions for Kevin McClelland, send him an e-mail at

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