If I change from a points type distributor to a stock HEI do I need to make any changes to the HEI distributor (The hei is an 70's model) to keep the timing correct for the older style camshaft already in the vehicle?

No, just make sure it has a full 12 volts going to it. You'll need new ignition wires, the ends are different.

Will all due respect, there is no knowing whether the timing curves of both units are identical? Could be the HEI's mechanical weights, springs and max limit differ from the points type, as does the vacuum canister.

Rob

As someone new to this, how would I be able to figure out the timing curves, etc. to make this work?

Originally posted by Pat Kelley:
No, just make sure it has a full 12 volts going to it. You'll need new ignition wires, the ends are different. Exactly!!! get rid of the ballast resistor on the firewall that the main coil postive goes into, also get rid of the resistor-style wire if you have it (it smokes when you put 12V to it; don't ask how I know). When I switched to HEI, I went with a 12 guage wire all the way from the ignition switch to the distributor after my little "incident". graemlins/beers.gif

If you get a replacement weight set, the curve characteristics are printed with it as well as spring rates for those weights. Vacumn advance on some can be adjusted and you need a timing light to see at what RPM total timing would be in by to adjust it...... HEI's are alot of fun when you understand how they work. I like the one's by D.U.I. that have the external timing adjuster dial on them.
http://www.performancedistributors.com/gmracedui.htm

scroll to the bottom! :cool:

So if I buy a new set of weights/springs for the distributor how do I match it to the cam specs? I am running a 929 cam (I think) and where would I find the needed information for the cam to match with the info supplied with the new parts mentioned above? (Sorry newbie at this so bear with me)