well just found this site and you guys have some pretty knowledgable members here and I was wondering if you guys could help me out. I just got my motor back for my 75 camaro and was wondering what would be the best type of distributor to use for my set up. It's a chev. 350 2 bolt block, 40 over and decked trw forged flat tops and eagle forged rods. it's a 10/10 cast crank and the heads are worked over 461 camel backs. they're fitted with 2.02 1.60 ferrera valves and have been machined for double springs, screw in studs and guide plates. the cam is a crane single pattern 302 total duration with 242 @ .50 with a total lift of .502. this is run with a victor jr. intake that's port matched and a holley 770 vac. sec. street avenger. the car has a th350 thats been built and a hughes 10in. 3500 h.d. convert. the back end is a 10 bolt w/ a posi and 3:73's. what i'm wondering is from this set-up would i want to go go with a vacume advance type distr. or go w/ a locked and curved set-up. this motor was built w/ the intent on nitrous being used, but not yet. I just don't wan't to buy the same part twice. some guys have told me the vacume advance will work, while others say the cam won't make enough vacume at part throttle for it to function properly. thanx for any info.

 

If you're gonna drve it on the street then get one with a vacuum advance canister (preferably an adjustable one). You'll still pull 8-10" of vacuum with that cam and it's plenty to work a well-adjusted vacuum advance canister.

You mileage, plug life and part throttle response will all be greatly improved over running without a vacuum advance.

Timing curve should look roughly like this:

12* initial
24* centrifugal advance, all in by 3000 RPMs
12 + 24 = 36* total advance, all in by 3000 RPMs
10-12* vacuum advance on top of that, all in by a low enough vacuum level that you can have all the vacuum advance "in" at a steady 50-60 MPh highway cruise speed. Probably about 10" of vacuum with that combo if I had to take a rough guess.

 

thanx, any preferences on aftermarket hei distributors?

 

If you already have an HEI just buy yourself an accel supercoil and control module. This will provide plenty of spark for you. It worked on our big block car that ran in the high 9s.