Originally Posted by 89k1500
I want to say it was heavier weights and lighter springs.
as for the link on Hot rodding your HEI Distriburator, I went there, read it, printed it off, and read it a few more times. Its good info I just havn't had time to implement said knowlege. Not to mention its cold as heck outside so my ambition level is low. =)
So should I do the timing before messing with the jets? (EDIT: Just read the last line of the last post, please ignore this question....lol )
I get it- COLD! lol
The timing is easier to get in the ballpark. In a lot of cases when using a GM HEI distributor, two medium or one medium and one light spring w/the stock weights will be about right. Then it's a matter of finding the initial timing it likes (good idle, good vacuum, carb idling on the idle circuit and not into the transfer slot), followed by limiting the amount of mechanical advance to keep the total timing from being too high. The total timing being too high is always the case because the initial timing is always higher than what the factory setting called for.
The MSD distributor uses bushings to limit the mechanical timing.,With the stock HEI you have to use screws like you saw in the link. When you get to that stage, if you need help someone can give you a hand w/that.
Lastly, during the process of finding the right amount of initial timing, you will need to readjust the idle mixture screws as you change the timing. And you'll possibly need to lower the curb idle speed to keep the mechanical advance from creeping in, or raise the idle speed if it gets too low.