Gary--This is something that I went through on my big block starter. If you've already eliminated the possibilities of poor battery connections &/or ground connection between battery, frame & engine, that makes me suspect the starter. If the solenoid doesn't fail to "kick-in" when hot & you're experiencing "drag or slow crank", it probably means that the starter is heat-soaking, causing the slow crank (A.K.A. "grunt"). I have tried heat shields, exhaust wrap, etc. & they only slightly helped. I finally broke down (litterally) & bought a heavier service starter with heavy windings & contacts & it took care of the problem. Many other starters will fit, but when you warm her up, it separates the lighter from the heavier starters. If your problem is that the solenoid won't kick in & hold, you can replace it with a higher quality solenoid or wire in a "hot-start" separate solenoid to handle the starter only (I had to do that on my Street Rod). Hope that some of this helps.
Good Luck!!!! P.S. The reply about checking the timing is a great idea, along with surveying the ground quality.
[This message has been edited by odie (edited 03-31-99).]
