Bonneville Speed Week And Chevy Engines - Performance Q&A

Kevin McClelland Mar 1, 2009 0 Comment(s)

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.

Sources: gmperformanceparts.com, msdignition.com

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

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