The Sad State of Motorsports - Performance Q & A

Kevin McClelland Jul 1, 2009 0 Comment(s)

Alky S-10
Q: I have an '86 S-10 with a 355ci small-block, RPM heads, roller rockers, a Torker II intake, 10.25:1 compression, a Comp 305H camshaft, a 750 Holley carburetor, a TH350 trans, and a 71/2-inch 10-bolt with 4.56:1 gears. The truck has run a best of 11.70 in the quarter-mile. I broke the gears and have 3.42s to replace them. How bad will this hurt me? The truck weights 2,800 pounds with 28x10.5 slicks. And what will be the best way to run alcohol? Thanks for your help.
Leonard Landry
Via email

A: Wow, we can't believe you've made it into the 11s without blowing up the 71/2-inch ring-gear rearend a long time ago! You could swap in the 3.42s, but it will definitely kill your performance with that camshaft and those tall rear tires. We'd recommend looking for either a late-model 2WD 8.5-inch S-10 rearend (quite rare), or a junkyard 8.8-inch rearend from a '79-and-up Fox-body Mustang. We know, we know, but they are cheap and plentiful in the wrecking yard, and the parts are easily available. All you would need to do is weld on new spring perches to mount it up. The width is within 1 inch of the stock S-10 rear, and you'd need to swap out your rear wheels. Then you would have a rearend that is inexpensive and will hold up to the power you're putting down.

Next, converting your truck to alcohol will take a complete upgrade of your fuel system. You need at least double the capacity from your fuel delivery system. A performance air/fuel ratio for gasoline is around 12:1. When you run on alcohol, the proper air/fuel ratio for peak performance is around 6:1. As you can see, you need twice as much fuel. Next, if you wish to go forward with the conversion, we'd recommend Quick Fuel Technology's complete alcohol carburetors and conversion kits, which include new boosters, metering blocks, alcohol-safe floats, and seals. Don't try just jetting up your current Holley carb. The passages in the metering blocks and the boosters won't move enough fuel and you'll burn up your little small-block. We don't know that you would gain enough performance to warrant the conversion. Running much higher compression could help. The only benefit you may see is reduced engine heat and increased consistency when the weather changes at the dragstrip.Source: quickfueltechnology.com

Way Over Bore
Q: I bought an engine rebuild kit from Powerhouse for a small-block 350 with 0.030-over pistons. Can a 305 block be bored to my pistons?
Allan McAra
Chilliwack, B.C., Canada

A: The stock bore on a 305 is 3.736 inches. Bringing it out to a standard bore for a 350 would require a 4.00-inch bore, which would remove more than 1/4 inch from the cylinder walls. Production 305 blocks will not accept that much overbore. The good news is that Gen I 350 blocks are very plentiful. Check with the machine shop where you were going to have your engine bored, and I'm sure there's a core 350 lying around or the mechanics will know were you can buy one reasonably. Sorry for the inconvenience.

Old School Meets New
Q: I'm an old-timer who's been playing with cars since the '50s. I'm currently running a 406ci small-block Chevy, Canfield 195cc heads, and a Lunati camshaft that specs out at 235 degrees duration at 0.050-inch tappet lift and 0.507-inch max lift. The compression comes in at 10.5:1, and it's topped off with a Weiand Team G single-plane and an 800-cfm Edelbrock carb. My old Corvette (around 2,900 pounds) runs great with this combination and the Richmond five-speed (street use only). I bought the Team G because it did an excellent job in a manifold comparison test by a major auto magazine many, many years ago. With the continuing improvements in manifold design, I suspect I'm leaving something on the table by not switching over to a current high-performance dual-plane. Is it enough to make the switch? Thanks.
Larry Delazzer
Via email

A: The decision to break into your little potent small-block would be determined by the way you drive the car. Yes, the Team G manifold is a very good piece, but some of the newer dual-planes will come close to rivaling the high-rpm power output of the single-plane. The biggest gain you'll see from the dual-plane would be in the 2,500-4,500 rpm range. With your 406 this could be as much as 30 lb-ft of torque over the single-plane. This is something you would really feel in the drivability. Then you have to ask yourself how much time you spend over 5,000 rpm. If the answer is little, then we'd definitely recommend a dual-plane design. Either the Weiand Stealth Air Strike PN 8501 or the Edelbrock RPM Air Gap PN 7501 would be a great manifold for your engine. From the testing we've done, you'd lose very little top-end horsepower (5-10) over the single-plane. Again, it goes back to the amount of time you spend in theses rpm ranges. If it was ours, it would be a dual-plane. Good luck, and keep playing with your Vette. It keeps us young!Sources: edebrock.com, holley.com

Technical questions for Kevin McClelland can be sent to him at chevyhi@sorc.com.

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