Ok i have a 79 350 in my 86 Z28. Old school vac. adv. and 650 cfm AVS thunder series Edelbrock carb. Torker II intake manifold and cam. Its set at 14 degrees advanced. When the engine is started it idles at about 1000rpm then quickly jumps to 1500rpm. but after driving a bit it idles at about 800rpm. The vac adv. is running into the manifold. not sure why the engine keeps loading now and then at idle.

 

lean it out then if it's fouling out plugs. Sounds like a timing issue if the rpms keep changing or a vacuum leak. Put in medium springs in the dizzy instead of the light ones.

 

what do you mean in the dizzy?

 

The springs in the distributor that control your rate of timing advance. He's saying use the heavier (not the heaviest, but the medium ones) so it doesn't come on so quick.

 

Then would it be a good idea to buy a new HEI cap set up like MSD.

 

no the parts store cap and rotor is fine, you just need a weight and spring kit which is $7 at the most from moroso or mr. gasket etc