October 2012 Chevy High Performance Q&A

Light Fuel

Kevin McClelland Sep 4, 2012 0 Comment(s)

Drive Like Granny

Q. I just picked up a ’71 Chevelle Malibu with 41,213 miles. It was an older woman’s car, used for church and local errands. It has the 307 with a Powerglide trans, A/C, P/S, and power drum brakes. I have a distributor out of an ’83 Camaro Z28 305 engine. I was thinking of getting rid of the points distributor; I am not positive if that would work or I should invest in an MSD unit. Also, is it worth it to change the intake and carb if it runs great? This would be in the future, since money is tight. I also have a 350 with four-bolt mains. I forget the exact year, but it is a one-piece rear main seal and would also be a consideration on the intake and carb for a future build.

Also what size wheel and tire combos fit? This is not my first Chevelle—I’ve had about 15! I think I remember having 15x8 Corvette Rallys all around with 235/60-15 tires. I was thinking of going with old-school Cragars with 15x8 all around, or 15x7 just in front. Thanks for your help.

Jim Mangano
Via email

A. Fifteen Chevelles? That must be some kind of record for one guy! Which one did you like the best, and what would you do to get it back?

At its age, with only 41,000 miles on the clock, it probably rarely got up to operating temperature, and we’re sure it has quite a ridge at the top of the cylinder wall from the wear of the top piston ring. The first time you really want to air this thing out, the pistons are going to travel into uncharted territory at the top of the cylinder and break the ring lands on the piston. I’m sure that it will run forever if you drive it like its past 41 years. If you want to hot-rod your 307, make sure you’re ready to swap out the 350 you have in the garage.

Swapping out to a later HEI distributor isn’t that big of a deal. First, you will need to make sure you have a non-computer–controlled HEI. The ’83 Camaro was the second year of Electronic Spark Control (ESC), and the computer controlled the spark timing. It’s very easy to identify if you have an ESC distributor, since it doesn’t have a vacuum advance canister, and will have a wiring pigtail coming from it with a four-pin weather pack connector. If you have a standard mechanical advance HEI with vacuum advance, it will drop right into your 307. The only mod you’ll need to do to your wiring is to remove the resistance wire from the engine harness and replace it with a standard 12-gauge wire. This resistance wire is in the engine harness from the firewall bulkhead to the coil positive terminal and is used to reduce the voltage delivered to the points ignition. It will be the cloth-wrapped wire in the harness. You will need to remove the spade connector from the bulkhead connector and solder the new 12-gauge wire to the connector. Then, reinstall it into the bulkhead. This wire will then feed a full 12 V to the HEI with a full 12 V.

Finally, 15x8s will fit all the way around your Chevelle with ease. Also, they will drop right on with the standard 4-inch backspacing from the 15x8 Corvette Rallys. If we were buying a set of Cragars for your ride we’d go for a little more backspacing to give you more clearance for the front tires. They will get a little tight on turns with the on-center backspacing. Cragar offers the 15x8 SSs in a 4.25-inch backspacing. Also, we’ve run as large as a 255/60-15 tires on ’70-and-up A-bodies. The wheelhouses and rear-wheel openings are larger than the ’69-and-earlier models.

Hope all this helps with your budget enjoyment. Yes, a full MSD Ignition setup would be the bomb. If you can recycle parts out of the garage for a while, you can enjoy your Chevelle while saving your pennies.

Sources: cragarwheel.com, msdignition.com

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