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Used Parts Play - Performance Questions and Answers

Performance Q&A

Kevin McClelland Nov 1, 2006
0611_chpp_01_z Used_auto_performance_parts Engine 2/1

Well, if you're like me, you look for deals anywhere you can find them. Swap meets, junkyards, eBay, Craigslist, and the classifieds; they are everywhere. Sometimes identifying those chunks of gold can be difficult. As I have mentioned in earlier columns, is a great resource for casting numbers.

Last week, our pal Ken Casey at Burt Chevrolet was telling me a story about a gentleman who had purchased a set of seats from a wrecking yard for his early Chevy. The seats were out of a late-'90s Cadillac that was equipped with seat warmers and full power. The man was looking for the connectors that would plug into the seats so he could easily wire them up. Well, with the extensive option list that the donor Cadillac could have had, including various seat options, Ken wasn't able to help the man with his connectors. They would have had to order in a few different sets, and they are very costly. What would have made the identification of the seats a no-brainer would have been to have the donor car's Vehicle Identification Number (VIN). After '90, all GM cars identified the options within the VIN. It's amazing the amount of info you can get from the VIN at a GM Dealer.

I love wandering through our local Pick-n-Pull, looking for electric cooling fans. Our yard will have deals on cooling fans from time to time, selling them for $10! I found one several months ago for my '80 Malibu Wagon race car. It was from some mid-'90s Cadillac. Did I get the VIN number off the car to identify if it had HD cooling? Of course not! If I need to change the electric motor or fan assembly, I'll be up a creek! If it dies I guess I'll just go to the yard and get another one. However, I will get the VIN next time.

Ramjet Engine Swap
Q I saw a RamJet crate engine swap into a '92 Camaro RS in one of your sister publications. I would also like to do this swap, as I have a '92 RS with a 305 TBI engine, and I have a 700-R4 trans that I would like to keep. I printed the article, but was wondering if you could direct me as to where I could find more specific information on what is involved with the swap. Especially regarding the speedometer, tachometer, oil pressure, and amps. Also, how would I keep my torque-converter lockup and the air conditioning?Dustin Meger

A The RamJet is a great EFI-equipped crate engine to upgrade your RS Camaro. Yes, many of the factory-equipped gauges and controls will be compromised if you swap out the engine with no regard to the original PCM computer. Our friends at GMCOPO have developed a line of jumper harnesses that will allow the original PCM to control the various vehicle-specific tasks (i.e., TCC apply, fan and A/C control, tach) while the RamJet MEFI 4 computer runs the engine. Since you keep the original PCM live, it will also output the electronic speedo signal. Give Tom Woodside a call at GMCOPO for the proper wiring harness adapter components at 248.275.5828; he will help you have your cake and eat it too!Source:

Stroker Rod Knock
Q I'm building a 383 small-block. The block was bored out to 0.030 inch over. I have put in an Eagle rotating assembly. The stroke is 3.750 inches, and the rod length is 5.7 inches. The cam is an Edelbrock with the duration coming in at 232/234 at 0.050 inch tappet lift, and 0.488/0.488 inch max lift. I'm also using a Summit dual-idler geardrive. I set my timing marks up with the crankshaft at 12 o'clock, and the cam at 6 o'clock. The problem is as I rotate the crankshaft off of TDC and just before the No. 1 piston can get back to the top of the exhaust stroke, a cam lobe hits the No. 2 rod and all stops! Not sure where to go from here to fix it. The rods look like they are installed correctly. Can you give me some help? Thanks.Ron SagerSacramento, CA

A When building a performance stroker engine you should mock up the rotating assembly several times before the final assembly. This is where you will find these little surprises like the rods hitting the camshaft, the pan rail, or the oil pan, piston-to-valve clearance issues, and other fun things. Any of these problems will require some type of clearancing, and you wouldn't want to do any of them with a freshly cleaned, ready-to-assemble engine. Installing a 3.75-inch stroke crankshaft in a 350 block brings 5.7-inch-long rods in very close proximity to the cam lobes and the pan rails. The 400 small-blocks used a special 5.565-inch-long rod that had a specially profiled big end. In a small-block buildup, cylinder Nos. 1, 2, 5, and 6 are always the closest. This is due to the camshaft lobe phasing. With the rotating assembly, you will need at least 0.050 inch of clearance between it and any other components. With your Eagle capscrew-type rod, it's very easy to clearance the rod to clear the camshaft. Unfortunately, you have probably already balanced your rotating assembly. Whatever you take off of the four rods listed above, you will also want to remove the same amount of material off the rest of the rods. This will keep your balance as close as possible.

Sorry that we don't have an easier answer. Unless the rods are specifically designed for stroker applications, you always have to clearance the rods for the camshaft in a 383 combination. Good luck.

Tired Monte Q I have an '86 Monte Carlo SS that I bought new. It's been my daily driver off and on for 20 years, and now has over 230,000 miles on it. It's getting pretty tired, and I want to replace the 305 with a crate 350. I still have to pass an emissions test annually. I've spoken to the local dealer and they tell me I have to replace it with another 305. I know other people have put 350s in their cars and still pass emissions. Can you tell me a part number for a crate engine I can put in that will keep the sniffer happy? Thanks for your advice.Bill WivelSahuarita, AZ

A You know that the dealer is going to say "Stock is right!" Most of the OEM dealers don't want to deviate from stock because of emissions laws (and their poor understanding of what will actually pass emissions). Let's put a package together.

We would start with the original GM Goodwrench 350 crate engine. They have sold millions of these engines over the years, and it's a great foundation for performance builds. This long-block engine, PN 10067353, is the replacement engine for all '79-and-earlier passenger cars. It is built from all-new components that spec out at 8:1 compression, 1.94/1.5-inch valves, 76cc chamber iron heads, cast crankshaft, four-bolt mains, and cast-aluminum pistons. On the engine dyno, equipped with the stock Q-jet manifold, Q-jet carb, cast-iron exhaust manifolds, and dual exhaust, the engine produces 230 hp at 4,500 rpm, and 330 lb-ft of torque at 3,200 rpm. This is a dead-stock 350 that will easily pass any emissions test Arizona wants to throw at your Monte Carlo.

As I said, this engine is a great foundation for a mild-performance engine. We would install an Edelbrock 3701 Performer manifold equipped with provisions for the EGR valve, an Edelbrock Performer camshaft originally designed for the LG4 305 engine back in the mid-'80s. This cam is specifically designed to work with the factory computer-controlled system and the computer-controlled Q-jet carb on your Monte. It's sold under PN 3702 and specs out at 194/214 degrees duration at 0.050 inch tappet lift, 0.398/0.442 inch max lift, and is ground on 112 centers. Yes, this is a very mild camshaft; however, it builds great torque with the low-compression 350. To round out your package, go with a set of Edelbrock TES headers. They offer a tubular exhaust system that fits the H.O. Montes with the high-flow four-bolt catalytic converter. This header system is sold under PN 68793 and will bolt right into your Monte if you upgrade to the high-flow converter. With this package listed above, your engine will step up to 275-plus horsepower and over 350 lb-ft of torque, and it will make great power from idle to 5,000 rpm. The best part is that the smog police won't even know that the long-block has been touched. All components of this build have been certified by the California Air Resources Board.Source:

Gear GrindQ I've got a 355 with a steel crank, Scat rods, and D-dished forged pistons for use with a blower. That's where I'm heading with this combo. I have the Comp Cams Nitrous or blower cam, 292 duration and 0.501 inch max lift. I just put the heads on the engine yesterday, but I'm getting conflicting arguments about my Pete Jackson geardrive and its harmonic something-or-other. I figure it's going to about 500-550 horses. Is there anything to worry about? Should I sell my geardrive and get a chain? Money is a factor here. Any input would be greatly appreciated...I mean, I saved up for the geardrive, thinking it was stronger. Thanks for your time.Michael Campagnoni

A Geardrives are the most durable camshaft-drive system available. Do they transmit crankshaft harmonics from the firing pulses of each cylinder back into the valvetrain? Yes. Is it a big deal? In your application, no. Where the geardrives get into trouble is when you're pushing the valvetrain dynamic to the max. The firing harmonics will aggravate the valvetrain stability. The firing harmonics will also affect the spark timing at the end of the camshaft where it drives the distributor. The best drive system for isolating the valvetrain from crankshaft harmonics is a beltdrive. Jesel released the first Gilmore belt drives for Chevys over 30 years ago. The rubber belt dampens the firing pulses.

Again, for your application, enjoy the whine of your Pete Jackson geardrive. Good luck with your blower adventure.

Impersonator Lite!Q This question concerns the article on the Impersonator buildup. Would you get similar results with 350 cid? I understand it would be considerably less on torque and horsepower, because it is less cubic inches. Or is this one of those combos that is optimal with the bore and stroke of the 406? The reason I ask is I already have a 350 with flat-top pistons, Vortec heads, an Edelbrock Performer RPM intake, and either a 650 Edelbrock or a 700-cfm Holley carb. I have not made a decision on a cam, but had considered a Comp Cams XE274. This engine is going in a '64 Chevelle with 3.73:1 gears, a four-speed manual trans, and about 27-inch-tall tires. I figured that you have seen and built lots of combinations that work well, and have some very good ideas and info. Thanks!Mark Richards

A The Impersonator was really a cool buildup. Sometimes you will fall into a killer package for the money, and that engine is one of them. Will those same pieces make a good-running 350? Absolutely! Now, your statement that we have some very good ideas is a real stretch...let's see if we can help.If you look at the power that the 406 made, it comes in at 428 hp and 525 lb-ft of torque. If you do a little math, that equates to 1.05 hp per cube and 1.29 lb-ft per cubic inch! Now, that last number is a biggie. One benefit of using the smaller-displacement 350 is that the small Vortec cylinder heads won't run out of air as early in the rpm curve as they did on the 406. The 406 had a horsepower peak of 5,000 rpm. With the correct camshaft, your 350 will peak around 6,000 rpm. This will carry the torque much higher in the rpm band, producing almost the same horsepower as the 406. The engine will lose some of the torque benefits of the large-displacement engine. Then it's time to look at camshafts.

You mentioned that you have an interest in using the Comp Cams XE274. That is a great camshaft, but for your buildup it's a little on the big side. You will give up too much torque with that camshaft, and only gain a few horsepower over the XE268. The 268 specs out at 224/230 degrees duration at 0.050 inch tappet lift, 0.477/0.480 inch max lift, and is ground on 110 centers. Yes, the 274 only has around 6 more degrees duration, but again, your Vortec cylinder heads run out of air by the time the engine can take advantage of the extra duration.

I've run a very similar engine at Flowmaster and produced numbers of 400 hp at 6,000 rpm and 434 lb-ft of torque at 4,100 rpm. This is with the XE268 camshaft, Performer RPM manifold, and ported L98 aluminum heads. The engine produces 352 lb-ft of torque at 2,000 rpm! The XE274 produced 407 hp at 6,000 rpm, the same torque at 4,100; however, it lost 20 lb-ft of torque at 2,000 and 2,500 rpm over the smaller camshaft. This will scoot your Chevelle around nicely. Have fun with your project.

Can I Breathe?Q What is the cfm rating of a stock TPI air-cleaner assembly on a third-gen Camaro? Nobody seems to have an answer. I'm asking because I came up with a custom cold-air induction system using a TPI air cleaner for my carbureted '86 IROC-Z. I replaced the original LG4 with a kick-butt 350 completely rebuilt to 355, fed by a 4-inch high-rise aluminum intake and an old Holley 750-cfm 4150. Because of extremely low hood clearance, with about an inch left at the front of the car, I couldn't find any air breathers that would fit under the hood. I tried several different models; the ones that would fit were way too restrictive. I bought the Edelbrock ProFlo 1000 and even had to shave off 1 inch at the base so it would fit. After installing headers and a 3-inch cat-back exhaust, the heat coming off those headers melted the foam filter into the carb. So I came up with an airbox and bought a TPI air cleaner assembly at a junkyard and created my own cold-air intake system. It looked OK and it solved my problem. Having too many problems with the old Holley, I replaced it with a new 600-cfm Edelbrock Performer 1405 last year and decided to build a newer, nicer-looking airbox using the cover and base from a regular 14-inch air cleaner.

Some say the 3-inch intake is too restrictive. That's the 3-inch air outlet on the stock TPI breather? OK! Then why am I seeing all kinds of aftermarket TPI plenums and throttle bodies rated at 1,000 cfm using the same 3-inch air-breather assembly? Why do I not see a bigger 4-inch or even a 5-inch throttle body out there? Sorry for the long letter, but this is the only way to explain my problem.Rob MitchellOttawa, ON, Canada

A The stock Camaro hood heights have caused many a problem for high-performance intakes on small-blocks and big-block engine conversions. You've really come up with a workable solution for this problem. Engines need large doses of fresh, cool air to produce good power. You have some good questions, so let's take a look.

Yes, the 3-inch tube that connects your air cleaner assembly to the 14-inch air cleaner housing would seem to be a problem. However, using a SuperFlow SF600 flow bench flowing a straight section of 3-inch-od, 0.063-inch-wall tubing at 28 inches of water gives you 828 cfm of steady-state flow! Now, your 355ci engine has a max flow of 668 cfm at 6,500 rpm at 100-percent volumetric efficiency! At that engine speed, you've driven well past the peak V.E. of your engine. If you're still at 90 percent we would be surprised. At 90-percent V.E. your engine is ingesting 601 cfm. With all of this said, the 3-inch tubing will flow enough air with 30 percent extra to spare

Do we know what the third-gen Camaro air-cleaner assembly flows? No, we've never had the opportunity to check the airflow on that assembly. If you are using performance-type air filters, like K&Ns, they will support the airflow requirements of your 355 with no problem. There are water baffles installed below the filters in your assembly. Removing those will help free up the air getting to the filters. You will need to be careful not to drive the car into too deep water.

Can we answer the reason you see 1,000-cfm throttle bodies for a 305-cid engine? There is only one answer: overkill. We've made over 440 hp through a stock L98/T1 throttle body. If you really drive the cubic inches of your engine up there, yes, the engine would respond to a larger throttle body. A 1,000 cfm? I think not.

Vette SledQ I own a '77 L48 Corvette. I love the car, but wanted it to run a little better without replacing the engine. I ran a straight 2-inch dual exhaust, put in a new cam with 214/224 duration at 0.050 inch tappet lift, 0.442/0.465 inch max lift, an Edelbrock dual-plane manifold, and an Edelbrock 600-cfm carb. A friend offered me a deal on a set of 202 heads, and I think this is where I went wrong. The heads are 76cc chambers with some port work. The car sounds great, but doesn't run as good as it sounds. Has crap for low-end torque, and only seems to pull well above 4 grand. The car only shows 22,000 miles, and I believe it because when I pulled the heads, you could still see the crosshatch in the cylinders. This is why I don't really want to mess with the pistons. It will run on any kind of bad gas, and no matter how high I run up the timing I can't make it knock. I know I need more compression. If I went to a set of 194 heads, with maybe 58cc, do you think that would do the trick? I can probably get these with or without port work. Thanks for your time.Bill Esper

A Those L48-powered Vettes should never have been sold. They produced a whopping 180 hp! How sick is that when the Corvette is supposed to be your company's flagship sports car? The L82 cars with their 210 hp barely gave you a thrill. You are going in the right direction stepping up the performance. Like you said, I think you stacked the deck against yourself.

The L48 engines came from the factory with 8:0:1 compression. They have dished pistons, 1.94/1.50-inch valves, and 76cc chambers from the factory. Who knows what type of port work your friend had done to your heads? Also, when you installed the heads you probably used aftermarket head gaskets that were thicker than the stock '77 gaskets, taking more compression away from your build. Combine this with stepping up the camshaft duration and it kicked you right in the shorts! If you go to a set of 58cc heads using factory-style head gaskets, it will boost your compression ratio up to 9.6:1. This will make a huge difference in the output of your engine. Now, taking this a step further, we wouldn't go with a set of iron 305 heads. We would either pick up a set of rebuilt or new L98 aluminum heads. These are the same heads used on the 350 H.O. ZZ4 crate engine. Between the smaller 58cc chambers and 1.94/1.50-inch valves, you will see the benefit of the 165cc inlet port. This will build great torque and support the horsepower potential of the rest of your combination. You can get these heads new from GM under PN 12556463. If you shop around, you should be able to pick them up for a very reasonable price. You will need to change over to center-bolt valve covers (stops leaks) and to rail-type rocker arms. The valvesprings on these heads will work perfect with your camshaft and the heads will require no machine work to match your max lift. Also, pick up a set of head gaskets, PN 10105117. These gaskets are 0.026-inch compressed thickness. This will reduce the quench clearance to give you better mixture motion in the combustion space.

Shop around for the best price from GM Performance Parts dealers around the country for the parts listed above. With your camshaft and manifold and these heads you should be close to the 300hp range. This will be a major step up from the 180 hp that your Vette came with. Enjoy.

Rocker ActQ I have a '98 Chevy 350 I am building an engine for and need to know if I can change the rocker arms from a 1.5- to a 1.6:1, since it has computer-controlled timing. Any advice would be appreciated.Kevin Hults

A Going from 1.5- to 1.6-ratio rockers isn't a problem with your computer-controlled timing system. Where you can sometimes run into problems is when aftermarket camshafts create valvetrain noise from increased valve velocities. With the increased valve speed you may see increased noise from the valves closing, or overtaxing the valvetrain like the lifters and springs. The computer may pick these noises up through the knock sensor and, thinking it's hearing spark knock, retard the timing.

These are rare cases, and it's usually when you go crazy with your camshaft selection. You won't see any of these problems with a rocker change, and if you guys have any questions about the cams that will work with onboard electronics, ask the manufacturers. They have tested them in your application and can warn you of problems.

Short To The Right!Q I have a '69 Camaro that has what I think is a unique problem. The steering on this car will turn normally to the left, but turns short to the right. I cannot tell that this car has ever been wrecked; in fact, the front suspension looks original, due to the factory undercoating on parts of it. I have changed out the steering gear and also have centered the steering twice, to no avail. The car has original-looking disc brakes. The tie-rod ends don't seem to be the same length, and I don't know if this matters. Thanks for your help, from a 62-year-old hot rodder.Jerry Palmer

A I'm jealous. I wish that I had just one of our Camaros back that I've owned over the years. After watching the Barrett-Jackson auctions I still can't believe the money those first-genie cars are bringing. Congrats, and enjoy your Camaro. Now let's keep you off the curbs on those right turns.

The Camaros came equipped with three different-length outer steering arms, mixed and matched depending on the steering type and the ratio of the steering gear. The shortest arms were used on power-steering standard-ratio and Z/28 fast-ratio manual boxes. The short arms measure approximately 5.25 inches from the spindle centerline to the tie-rod attachment hole. The medium-length arms were '67-68 manual steering gear. These measure out at approximately 5.50 inches. And finally, the long arms measure approximately 6.0 inches and were used on the slow-ratio manual steering gear. I understand that the undercoating and road grime lead you to believe that your front end is original. However, back in the early part of your Camaro's life, it could have been introduced into a curb or a slight fender bender that would have required some parts replacement. They will all swap out with out any problem. The years have given the suspension a blended state of color.

This is the only thing that I can think of if you have centered the steering gear. If you have two different-length outer arms it would cause your problem. Get out a tape measure and check out your arms. Hope this leads you to your problem (and solution).

Will not lightQ I have a '94 LT1 that has been transplanted into my '89 AWD S-10 Blazer. The problem I have is that the engine will not start after sitting a couple of hours, unless I spray starting fluid into it. The VATS has been removed as well as having the computer calibrated for the speed sensor in my TH700R-4 and all the unnecessary stuff has been deleted. The following parts were replaced by my dealer: PCM, fuel injectors, pressure regulator, Opti-Spark, ignition module and spark plugs and wires, all to no avail. I have scanned the PCM myself with a code reader that I rented from my local parts store. It says there are no codes, but the "check engine" light still comes on and stays on after the truck is running with the starting fluid. Can you point me in a direction that may resolve this problem? It's already kept me from getting the truck on the road for over a year now! Thanks.James GravesStillwater, OK

A I checked with our buddy Tom Woodside at GMCOPO for his thoughts. Having done a ton of LT1 and LS1 swaps into earlier hardware, this is what he had to say:

"It sounds like a wiring problem at the fuel pump or a leak at the fuel-pump coupler in the tank. All this assumes that the correct fuel pump was used for the LT1 swap. If the truck originally had a LB4 TBI 4.3L V-6, then the pump will not produce the necessary pressure (around 42 psi) for the LT1's PFI injectors. To handle the fuel needs of the LT1, install a L35 CPI engine fuel pump, GM PN 25163473.

"Check the fuel pressure during key-up. The LT1 fuel rail has a pressure tap. Does it shoot up to about 42 psi? Does the pressure stay up during crank or drop? If it drops during crank, verify that the LT1 conversion wiring harness has the fuel pump power staying hot during crank. If the power is at the pump during crank and engine running, key on, and the fuel pressure is low or comes up slowly, I would drop the tank and inspect the fuel-pump coupler hose in the tank. These have a tendency to leak or disintegrate from fuel additives. If the coupler is OK, then I would swap out the fuel pump. The S-10 pumps are also affected by fuel additives and start to lose flow.

"As for your 'check engine' lamp, I would check codes using a GM Tech1 or Tech2 type scanner to make sure that you are not missing something. Also, is the LT1 harness properly tied into the vehicle ALDL connector? Is the scan tool communicating with the LT1? If you clear the unknown codes with the scanner, does the 'service engine soon' light then go out? Hope this gets your S-10 on the road, and you can reach me at 248.275.5828 if you have any additional questions."

Tom, thanks for the great advice. From my experience I'd have to think that your lamp could also be related to the functions that you removed. Whoever recalibrated your PCM missed one of the functions. Dig back through the functions you bypassed and check them off. Hope this has helped and gets you on the road very soon.Source:

Can't we all just get along?Q I own a '00 Chevy Silverado and have put on a cold-air intake and a mass airflow sensor. Diagnostics say it is running too lean. Could you recommend a company/part that will deliver the extra fuel needed? Thanks.Nathan Schuetz

A You've run into a common problem of parts compatibility. Something in the component package between your cold-air intake and the aftermarket mass airflow sensor isn't making your PCM happy. If I had to guess, I would say it's the MAF sensor. Was it designed for your application? The specific frequency of the MAF must match the PCM's calibration. We would recommend standing on the company that made the MAF sensor and demand they send you a new one or the correct one. If it was designed properly, you shouldn't have any trouble codes or need to change out any other components to make your upgrades work.

Don't Shortcut Your LiftersQ I drive an '83 C-10 Chevy truck. Under the hood is a plain-Jane 350 stock crate engine from SDGC. It's equipped with a Performer intake, a 650 Edelbrock, headers, and Super 40s from Flowmaster. I just purchased an Xtreme Energy XE268H hydraulic flat-tappet cam. What kind of lifter and pushrods should I get? Thanks.Brad BrooksCorpus Christi, TX

A As you have probably read in other publications, flat-tappet camshafts have been failing with great regularity the past few years. A couple of reasons have come to light. First is the flood of low-cost, off-shore lifters being manufactured from inferior material and not up to GM tolerances. In the same timeframe, the oil companies have reformulated the motor oil, reducing the amount of zinc and phosphorous additives that provide high-sheer protection. Most of the OE engines now have hydraulic-roller tappets, which don't need as much high-sheer protection. And as engines wear and consume oil, these additives contaminate the catalytic converters, reducing their efficiency. Between the lifter quality and the reduction in additives in the oil, the cams got a double whammy and they were going flat on break-in.

We'd recommend going with high-quality lifters and pushrods from Comp Cams. They have very good lifters that meet the specifications of the GM tappets. Another trick is to use diesel motor oil for the break-in period of the camshaft. To be honest, we would run the diesel oil for the first 3,000 miles. These diesel oils should still have the high zinc and phosphorous content for at least another couple of years. This will give your camshaft plenty of time to get happy with the lifters.

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

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