April 2011 Chevy High Performance Q&A

Fuelish Pleasures

Kevin McClelland Mar 8, 2011 0 Comment(s)
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If this is the case and you’re still running the stock distributor, you need to swap out to an ’81-and-earlier HEI distributor or pick up an MSD HEI billet distributor (PN 8365). This fully adjustable distributor gives you features of all MSD’s racing distributors. Both the mechanical and vacuum advance is adjustable, allowing you to tailor the advance curve to your specific engine package. You will want to give your engine an initial advance of 16-18 degrees of timing with the mechanical advance coming in around 1,300 rpm and achieving a total advance of approximately 32 degrees of spark at 3,200-3,400 rpm. On top of this mechanical curve, add around 12 degrees of vacuum advance to squeeze the maximum fuel economy out of your engine package.

With the above advance curve, your 355 should be around 400 hp and 410 lb-ft of torque. If you had around 10:1 compression we’d push these numbers closer to the 420 range for horsepower. You are correct in expecting your engine to have great low-end torque with those cylinder heads, camshaft, and torque converter selection. Good luck finding the wheelspin within your little small-block!

Source: msdignition.com

Too Slow Monte

Q: First off, love the mag, especially Performance Q&A. I’ve got an ’85 SS Monte Carlo, completely street-legal, with a lift-off Harwood hood and a 10-gallon fuel cell. The engine is a 406ci small-block; an Eagle 4340 forged crank; ESP H-beam rods, 5.7 inches; Wiseco forged pistons; ARP main, rod, and head studs; Brodix Track-1 heads, 221cc inlets with 2.08/1.60-inch valves; a Lunati solid-roller cam (0.600/0.618-inch max lift, 258/268 degrees duration at 0.050-inch tappet lift, ground on 106 centers); Crane roller rockers; a Pro Comp single-plane intake; an MSD Digital 6 Plus and Pro Billet dist; and a Pro Form race series 750-cfm carb. It has a TH400 trans, a B&M Holeshot 3,600 converter, and an 8.5-inch 10-bolt with 3.73:1 gears, on 28x9 MT ET drag slicks.

Am I expecting too much from this car? The best e.t. so far is 7.80 at 89.6 mph, with a 1.76 60-foot. Buddies and fellow gearheads all estimate 6.90s-7.00s. Does this sound doable? Is this an OK cam for the engine? And how much more miles per hour can be expected with 0.2-quicker 60-foot? Any info would surely be appreciated. Thanks, and keep up the awesome job you do!
Chris Chace
Huntingdon, TN

A: We’re going to have to side with your gearhead buddies. With the engine you have built, your Monte should be close to the performance they’re calling out. Let’s dig a little deeper into your build to see why you’re not seeing this type of performance.

First of all, the 406 that you’ve put together is one nice little small-block. This engine should make an easy 600 hp and a good deal of Monte-moving torque. However, with your build this engine is going to be a higher-rpm 406. We’d say the real powerband of this engine is between 4,500 and 7,500 rpm. That said, the car needs to be geared and convertered accordingly if you expect the e.t.’s you’ve listed. Also, if your suspension, gearing, and converter were working together you should easily be in the high 1.50 range for 60-foot times. Our ’80 Malibu wagon in bracket trim with our 460hp 350-cid small-block has an average 60-foot of 1.56, and has had an absolute best of 1.51! This is with an eighth-mile time in the 7.40 range, and a quarter-mile time in the 11.60s-11.70s. We are currently running 4.88:1 gears with a 28x9 Hoosier tire in the rear. To make the suspension work, we’re running Moroso Super Trick coil springs front and rear, and Competition Engineering adjustable shocks front and rear. We’ve also raised the upper pickup points on the upper rear control arms at the rear axle to move the instant center of the rear suspension back and down to plant the tire. If you are experiencing wheelspin after the launch, you’re not getting the weight transferred to the rear tires. This all comes from the car not rotating because of its steep gearing and stock suspension.

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