Moving up to a hydraulic roller package is the right direction. To reach your 400-425hp goal, go with a Comp Cams Xtreme Energy hydraulic roller. Check out grind XR276HR, which specs out at 224/230 at 0.050-inch tappet lift, 0.510-/0.510-inch max lift, and is ground on 110 centers. This cam will work with either your 408 or will make a ton more torque in your 454. As for the inlet and carburetor, I really like Q-jets, and if yours is in good condition and performs well, stick with it. Go with an Edelbrock Performer RPM 2.0 Q-jet. This manifold will accept the Q-jet carburetor with no adapter plate, and it also accepts a square-flange carburetor on the same manifold. PN 7164 will match your oval-port cylinder heads.
The TH700-R4 transmission is probably one of the best upgrades for any big-block-equipped performance car. Lowering the cruising speeds of a big-block will lower engine temps, fuel consumption, and noise considerably. A performance rebuild and the Corvette torque converter will be a perfect match in your Chevelle. Then you can enjoy the cruiseability of your SS.
Sources: compcams.com, edelbrock.com, joegibbshotrodoil.com
Things That Go Boom
Q I have a Chevy 383 with an all-cast bottom end. The cam is a Comp Xtreme Energy with advertised duration of 270/278 and a max lift of 0.482/0.489 inch. I have a fresh-worked set of 041 Chevy castings with 2.02-/1.60-inch valves and Crane Gold Billet 1.6 roller rockers, Edelbrock Victor Jr. intake, out-of-the-box Holley 750 double-pumper, MSD Pro Billet distributor, 6AL Box, and Blaster 2 coil. It has an adjustable NOS two-stage dual-shot cheater plate system. I've only sprayed 150 to the engine. The system can go 50-175 on the first shot and 150-250 on the second. The drivetrain is a TH 350 trans, an 8-inch Vega converter, and a stock rearend with 3.73:1 gears. The '87 SS Monte Carlo cruises on the stock fuel pump, but at the track I run two Holley Blues and a 5-gallon fuel cell feeds it. Its best was 11.13 at 123 mph. I'm working on an S-10 with the same build except for the heads and cam and 4.10:1 gears. Would a set of 220cc Motown Street heads with 64cc combustion chambers and 2.08-/1.60-inch valves help the power? What if I added a Comp Cams Nitrous HP with 284/305 duration with 0.507-/0.525-inch lift?
You have to love technology, I'm sending out this e-mail to you out of my backyard and under a tree!
Bobby BaxleyVia e-mail
A Have you ever heard that the fuse is lit and you better run? To move your Monte that fast, you're making well over 600 hp and a ton of torque with the nitrous. We've seen things live for much longer than they should, but we wouldn't recommend building on this combination any further. You may have lucked into something that will live for now.
Adding the above components to your current engine package will only raise the engine speed. Larger cylinder heads, added duration, and lower rearend gears are a recipe for disaster. Cast cranks and cast pistons have a limited engine speed life. If I had to guess, your Monte Carlo is going through the lights around 6,500, based on a 26-inch tire and the slippage of the Vega 8-inch converter at the 123-mph speed. The components you have listed will push the horsepower peak well over 7,000 rpm. Will your cast components take that type of abuse? We think not.