I've got two GM HEI units. One from my70 el camino, and the other from an old Chevy truck. I noticed that the weights have different numbers on them. The ones from the el camino are "105" and the ones from the truck are marked "130". Does anyone know which ones are correct or where to go to find out? Thank you!

I think you might find the following article helpful.

Changing the Advance Curve on HEI Distributors (http://www.boyleworks.com/ta400/psp/distcurve.html)

I did.

Once I replaced a dying starter, the info in this article helped me get my total, centrifugal and initial timing set correctly. I'm VERY pleased with the result. My setup was so starved for advance, that once I got it set correctly, the improvement feels like I added a 100 HP of nitrous.

And that makes this motorhead VERY happy. :-D

How old's the truck?