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Bonneville Speed Week And Chevy Engines - Performance Q&A

Kevin McClelland Mar 1, 2009

Bonneville Speed Week
Whenever you hear the words "Speed Week," the first thing that comes to mind is the Bonneville Salt Flats Speed Week, which is held every August. This is where man and machine have set out to break speed and endurance records for more than 60 years. Many of the records have stood for decades. Many of the classes contested at Bonneville have very specific rules and requirements for vehicle and engine combinations.

Every year the week before Bonneville, many of the local racers stop by our facility in order for me to give them a final once-over on the chassis dyno. This is when my Speed Week really starts. This past week we tested three cars for a local builder, Vern Tardel, who specializes in early Ford iron. The first of three roadsters we tested was his record-holding blown and injected 283-cid flathead burning alcohol stuffed into a '27 T roadster! This little engine has a 6-71 blower stuffing over 17 psi of boost through the little L-headed engine. Next was a very nostalgic 32 highboy roadster with a mild 283 flathead with fuel injection. Finally (now we're getting to the Chevy), we tested a brand-new '32 that Tardel built for the Mariani Brothers. It has a 258-cid SB2 NASCAR-inspired small-block with two four-barrels on top of a sheetmetal tunnel ram. This little mouse produced 530 hp at 9,600 rpm on the engine dyno when it was sent out from the builder. Tardel installed the engine, Jerico trans, and low-friction 9-inch into this very nice E/Street Roadster. After working through several days of bugs, we finally ended up with 520 hp at the rear tires! This was a very nice gain from the engine dyno.

After my week was done, all I could do was wait by the phone for the record runs. The Mariani Brothers smashed the E/Street Roadster record by 11 mph and bumped it up to 185 mph. Tardel, with his nasty blown '27, pushed his own record from three years ago up 11 mph from 166 mph to 177 on the first run.

Remember when I mentioned endurance? To set a record you must make your first run and then the car goes to impound. The next day you must make a return run to set the record. After Tardel had made his first run and the car was in impound, they found water in the oil from a cracked block! Who do you think they blamed that on? Of course that would be me! They said it was because it made too much power. Maybe one of these years I'll get the chance to make the Speed Week trials. I've heard that it's a life-changing experience! Check them out at

LS Bracket Bomber
QNormally I'm not one to invent a new mousetrap. However, with all the new equipment for the LS series Chevy engines, I keep thinking that this is something I could do. Currently I'm using a mild iron-headed big-block Chevy to run 10 flat in my bracket car. It has been 9.79 at the track, but the conditions were excellent. Currently it is 2,588 pounds with me in it and a Powerglide. With an LS engine I could cut some weight and go maybe 9.50s with a good solid engine.

I've got some questions though. Where does one mount the front engine plate on one of these? The water pump looks like it may not work the way Gen I engines do. The LS engines are missing one bolt hole on the trans mount flange. I understand the hole was left out here because of interference with a head bolt. Couldn't I just drill a shallow hole here and use a stud? This way I could use my Powerglide. I think converter issues and an AFI flywheel have been worked out by the aftermarket.

The ignition system and fuel metering system are where I'm really confused. How do I use an EFT with my current throttle stop and MSD 7AL3? I'd like at least 400 ci, and a production block with L92 heads might help me reach my goal. Things like cams, rocker arms, and oil systems have been addressed by the aftermarket already. Lots of choices here. Your thoughts? How would you approach this project? I'm all ears.
Bruce Guertin
Via email

AI've been trying for weeks to figure out how to throw this project idea at Henry D. I also want to step up our stocker/bracket wagon, and I was looking to swap an LS-based engine into the engine bay. Thanks for giving me a reason to throw the pitch. It's a great idea, and yes, the aftermarket has really stepped up with rotating assemblies, valvetrain, cylinder head, manifolds, and so on.

You could make front engine plates that would sandwich between the water pump and block. Compared to a small- or big-block, it would be a little tougher. The LS engines utilize three bolts per side and are 8 mm in diameter. These are slightly larger than 5/16-inch fasteners. Making killer power held in by three 5/16-inch fasteners per side doesn't cut it with me. I would make up side mounts off of the factory mounting pads on the side of the block and bring them forward to the front of the case with a 90-degree flange. Then you could attach front mounting plates to something much more secure.

Don't worry about the one trans mounting bolt hole on the right upper location. It may be because of a head bolt location, but it's because GM reduced the rear flange depth of the block by 0.400 inch. When the LS family of engines was being developed back in the middle '90s, they wanted the engine to be as short and compact as possible. The rear of the block is as flush as they could make it compared to either a big- or small-block. We've run without that upper bolt hole for years without a worry.

You also mentioned that the aftermarket has stepped up to SFI flexplates, flywheels, and converters. The crankshaft flange is also moved forward 0.400 inch in relationship to the bellhousing flange compared to a standard small- or big-block. If you wish to use all new components, that's great; but if you want to do it on the cheap, use crankshaft spacer PN 12563532. This makes up the 0.400 inch of deficit in crankshaft length. You must also use longer bolts, which are sold under PN 12553332.

Finally, there are a couple ways to skin the ignition issues. The cleanest by far is the GMPP LSX controller PN 19171130. This is a standalone computer and ignition system that utilizes all the factory sensors to feed it the proper information to feed the eight-coilover-plug ignition. This small little box features programmable low- and high-rpm rev limiters, custom advance curves, and a step retard that you are able to program with the software supplied. This kit comes complete with box, wiring harness, and software. This makes it a no-brainer to plug and play any LS-based engine.

0903chp_02_z Bonneville_speed_week_and_chevy_engines Msd_ignition 2/2

MSD also offers two ignition systems for carbureted LS-based engines. The 6LS has all the same features listed above except for the wiring harness. MSD says with a handful of connectors you can use a factory harness and wire in this controller. PN 6010 is designed for the 24-tooth reluctor wheel and is for LS1/LS6 engines, and PN 6012 is for the 58-tooth reluctor wheel and is for LS2/7 engines. If you're stuck on using your MSD 7AL3 then you need the LS front distributor drive cover. This is an adapter front cover that mounts a distributor and mechanical fuel pump off the front of an LS engine. It is sold under PN 88958679. One of the pains of using this setup is that it requires you to use a small-block-Ford-style distributor and mechanical fuel pump. It also requires you to use an aftermarket damper.

If I were to make a bracket package that I wished to throttle-stop, I would go with a carbureted setup and use current throttle-stop technology. You could set this up for EFI and use a linkage stop, but calibration issues could be a real headache. A simple 4150 Holley would work very well with either an air or electric blade stop. GMPP offers three single-plane inlet manifolds for the LS-based engines. PN 88958675 is designed to work with LS1/LS2 and LS6 cylinder heads with the cathedral ports. PN 25534394 was designed for the LS7 cylinder heads. Finally, PN 25534401 is for the L76/L92/ and Gen III engines. No matter which cylinder heads you end up using, GM Racing has the manifold.

Finally, your engine. There are some really killer GM crate engines to start with. The one that I want to use is the CT525 6.2L, PN 19171821. This engine is based on the Gen IV 6.2L LS3 all-aluminum long-block from an '08 Corvette. The bore size is 4.060 inches with a stroke of 3.62 inches, which gives you a nice 376ci displacement. If you simply threw a 4-inch arm in this little puppy, you would have a cool 414 inches. GM swapped out the production camshaft for its ASA circle track hydraulic roller cam, which features 226/236 degrees duration at 0.050-inch tappet lift, and 0.525 max lift. If you slid in a nice 252/260-duration-at-0.050-inch-tappet-lift cam with 0.600-plus max lift, this engine easily would kick out close to 600 hp! Also, this little puppy would tip the scales right over 400 pounds. Compared to your iron-headed big-block, that would take an easy 250 pounds off the nose of your car.

OK, now I'm ready to start on my wagon. A few mounts, build a set of headers, and off into the 10s we go. This was the best way I could think of to do something different and get us into the Super Street class in the wagon. Looks like I have a serious sales pitch to throw. Good luck with your project.


Got to Love the Gas!
QI need your advice regarding my '82 Corvette. I spent two years trying to increase the performance of the L-83 engine with the Crossfire Injection system, which ended up turning mid 13s on nitrous. After I pushed out a cylinder head gasket, I was sure not going to the trouble to tear down the engine and not make some major changes.

I replaced the CFI with a Holley 670-cfm Street Avenger carb and an Edelbrock Performer intake (2101), an Edelbrock Performer cam (2102), Edelbrock Performer aluminum cylinder heads (60759), and Summit 1.5 roller rockers. Spark is supplied by a MSD 6AL box and an MSD Pro Billet distributor and coil. I have Stan's Tri-Y headers and, for the track, a Zex nitrous plate under the carb fed through NOS solenoids. I have a beefed-up TH700R-4 tranny with a 2,500-stall speed. My best time is 11.679 in the quarter and 7.51 in the eighth.

I wanted to keep the low-end torque and street manners because this was my daily driver at the time. I now have a trailer and another driver, but I still want to drive on the street occasionally. I would like to increase the naturally aspirated performance, and I think a cam change is my best bet. My question is what cam should I run for the best combination of street manners and ET? Are the heads holding me back, or are they OK with a bigger cam? Should I go roller cam or stay flat tappet? What is the estimated horsepower of the combination with the cam you suggest? Thanks for your assistance.
Clint Goolsbay
Via email

ZZ4 Mixer
QI have a new Chevrolet ZZ4 crate engine. There seems to be some controversy over the correct or optimal carburetor for this engine. Folks have made recommendations ranging from 600 to 770 cfm. Also, I'm using stock ram's-horn, cast-iron exhaust manifolds. Are these OK, or should I install headers? The engine is installed in a shortened '69 Chevy half-ton truck fame with a '51 GMC panel truck on top. The rig is used mostly for towing a small, 16-foot ski boat. Any help will be appreciated. Thanks.
Bob Smith
Via email

AThroughout the development phase of the ZZ4 engine package, two carburetors were used. For off-road use (performance), we used the PN 4779 Holley 750 double-pumper. This carburetor is perfectly jetted right out of the box for best performance. Second, we used a computer-controlled feedback Rochester Q-jet for an '87 LG-4 305 Camaro. This was the emissions phase of the project. This carburetor ran very well also, with a secondary hanger and metering rod change. The emissions Q-jet is rated at 650 cfm.

As for your application, everyone has been somewhat right! I would recommend a double-pumper somewhere around 650 cfm. For performance and light towing, this carb will give you great throttle response and drivability.

If you don't mind leaving about 25 lb-ft of torque on the table, keep using the ram's-horn manifolds. The cast manifolds will hurt your slow-speed torque below torque peak by upwards of 25 lb-ft. Yes, the cast manifolds are the "install them and forget them" part. Headers would present their own challenges with spark plug wires and sealing over the years. Either will work for your application. It just matters if you need to use all the torque that the ZZ4 has to offer. Good luck with your very neat project.


AWhat size jets do you have in that plate? Best case, your Edelbrock Performer Power Package is kicking out around 325 hp naturally aspirated. To get your C3 Corvette into the middle 11s you must be pushing out 475-plus horsepower on the Jones. That's quite a runner you have on your hands. Are you sure that you want to mess with it?

The Edelbrock Performer aluminum heads are focused on making great torque and all done by the 5,500-rpm range. They have a nice street inlet port that displaces 170 cc's. The heads flow well to 0.500-inch lift on the inlet side flowing 244 cfm. Anything above that amount of lift and the port gets saturated and doesn't flow any more air. Lifting the valve more than 0.500 inch won't really help your performance anymore. The exhaust will give you 175 cfm of flow at 0.500-inch valve opening and 183 cfm at 0.600-inch. Unless you are willing to throw out the baby with the bathwater, I would stick with these heads. Your package is very well thought out and is using all the torque you can produce. If you were to supersize the cylinder heads, you would need a new inlet manifold that wouldn't fit under your hood, a larger-cfm carb, exhaust headers, and so on. Let's look to a cam that will give you about 50 more horses and will work with all your other components.

Comp Cams designed its Nitrous HP line of camshafts specifically for street use with nitrous. They have relatively wide separation angles, and longer exhaust events to expel the added exhaust gases from the nitrous-enhanced combustion. Comp offers them in both hydraulic flat tappet and roller designs. What is interesting about street rollers is that the seat timing (0.006-inch lift) is much greater than their hydraulic flat tappet counterpart. This is because you can only open the valve so quickly off the base circle of the cam with a roller tappet. You can actually open the valve faster right off the seat with a flat tappet design. By 0.050-inch tappet lift the duration is the same, but the real story happens by 0.200-inch tappet lift. To have equal duration at 0.050 inch, the roller design has 8 degrees more inlet duration and 9 degrees more exhaust duration at 0.200-inch tappet lift. This is where the hydraulic street rollers really shine over the flat tappets. At really short street durations, the flats have slightly better idle quality, but it's all done by the time you stand on the throttle.

Check out Comp's Nitrous HP camshafts. I would recommend going with the hydraulic roller design, which is sold under grind number NX276HR. This camshaft specs out at 276/288 degrees duration at 0.006-inch tappet lift, 224/236 degrees at 0.050-inch tappet lift, 0.502/0.520-inch max lift, and is ground on 113 centers. The wider centers help reduce communication on overlap because of the added cylinder pressure from the nitrous load. If you can't afford to upgrade to the retrofit hydraulic rollers, go with the NX268H grind. This cam comes in at 268/286 at 0.006 inch, 224/236 at 0.050 inch, 0.477/0.490-inch max lift, and is ground on 113 centers. As you can see by the specs, the inlet lobe is quite a bit shorter at the seat timing numbers, which helps the idle quality. Check with Comp Cams for more information on both of these selections.

With the hydraulic roller camshaft swap you should easily have 375 hp with your current combination. With refinement, on the Jones, you should be well over 500 hp, which will push you into mandatory-rollbar territory with your Corvette. Great job with your Vette, and enjoy.


Confusing Shifts
QI am in the process of installing an LS2 crate engine in a '57 Bel-Air using an aftermarket frame. The part number of the engine is 19165484. What type of 4L60 transmission will work with this engine? I am set to use the '98-and-later Corvette one with a two-piece bellhousing. I just read an article on a website that said if your engine uses a 58x crank trigger, your only option is a 4L70 transmission. This transmission was used in the GTO, the Trailblazer SS, and the '07-and-later fullsize trucks and is unique in that it has an input shaft speed sensor. The 4L70 transmission has a slightly higher torque capacity than a 4L60, but the added input shaft speed sensor is a must for compatibility with a 58x PCM. Is this true? I could not find anything like this before we ordered the engine. I basically said "put your transmission on it and stick it in your hot rod and go." Any help would be greatly appreciated.
Jerry Cox
Ocala, FL

AEngine controls and transmission controls are moving faster than the speed of light these days. GM has now gone to installing transmission control modules (TCM) in the valvebody of the transmissions to communicate with the engine control module (ECM), which is responsible for engine management. Gone are the days when the powertrain control module (PCM) controlled both. This is where swapping in some of the latest of the General's trick parts gets rather tricky. Swapping in some of the newest powertrains requires that you use the TCM/ECM combo or go with aftermarket-specific controllers to manage your driveline.

The LS2 6.0L engine you have purchased from GM is the same engine that was released in the C-6 Corvette back in 2005. This 400hp beauty is a great street rod engine. Since you purchased the crate engine from GM, I must assume that you're going with GM's harness and controller for street rod/performance applications. This complete system sold under PN 19166568 and came complete with a harness, a controller, a mass airflow meter, a mass airflow meter mounting boss, a fly-by-wire accelerator pedal assembly, a pair of oxygen sensors and bosses, and complete instructions. This is a programmed ECM that supports the 58x reluctor wheel crank in the LS2 engine. However, this system does not have any transmission support, neither manual nor automatic.

To get to the bottom of the transmission control issue, we got some help from Marty Morris at Scoggin Dickey Performance Center. Morris told me of a standalone transmission controller kit (PN 12497316) that GM Performance Parts sells. This will control 4L60E, 4L65E, 4L80E, and 4L85E transmissions. The kit contains a wiring harness, software, and a connector for your computer. With this kit you can program shifting, part and wide-open throttle shifts, and shift firmness. With this GMPP trans control kit you can use your '98 Corvette transaxle assembly with no problems. The transmission controller will get its rpm speed, throttle position, and load reference from the engine management controller.

Good luck with your killer '57 project. Send us some pictures and an update when you get it running.


Budget EFI
QI have a new project, a '69 Chevy Blazer. I would like to put TBI injection on the 350 in the Blazer, but I need some guidance. I know that vendors would love to sell me all kinds of stuff, but I got a complete TBI setup with a harness (GM) off of an '89 pickup. How do I make it work? Thanks.
Jerry Zimmerman
Via email

AWouldn't it be nice if I could tell everyone how to make it work! Since you have a complete system from the '89 truck, you've won half the battle. However, you will need some support in the way of wiring and calibration to make the factory system work on a '69 engine. I recommend that you contact Howell Engine Development. Howell builds standalone TBI systems to retrofit systems using all GM throttle bodies, sensors, and ECMs. It has the ability to calibrate to specific engine combinations and to "calibrate out" functions not needed in your early truck. Howell can help with the "rewiring" of your factory harness. Over 50 percent of the wires in the factory harness can be removed because of emissions devices not on your early truck. Or you can purchase Howell's very popular TBI retrofit wiring harness. This harness is ready to plug and play with all the components you have from the '89 truck. This alone will save you so much time and headaches it's worth every penny.


Technical questions for Kevin McClelland can be sent to him at



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