Tach drive distributors

[Edward M.]

What parts of a tach drive distributor make them unique to a specific engine? The only things I can think of are the cam at the top of the distributor shaft, the springs for the advance weights, and the weights themselves.

I need to put together a tach drive distributor that has the correct components in it for a 1974 454 4 speed car.

How many different cams, weights, and springs did Chevy use?

[William C.]

Re: Tach drive distributors

The plate the weights sit on and pivot on are unique, as they control both the rate of advance to an extent, by the position of the pivot pin, and the total advance by different lengths of the slot in which the advance limit pin travels.

[Steve D.]

Re: Tach drive distributors

Ed

The link below will take you to a page on Dave Fiedler's site that lists several articles that he has written re: distributors. The article by the fourth bullet (All Transistor Ignition Distributors Are Not Equivalent)addresses the issues associated with your question. Although he is specifically addressing TI distributors, it generally applies to points distributors as well.

Steve

http://www.tispecialty.com/info.htm

[Clem Z.]

Re: Tach drive distributors

since it is a low CR engine i would just set it up for 36 total mechanical advance at 3000 engine RPM and go from there if you have any problems with pinging.