".......and I have great battery cables, heavy duty. But why great starting when cold, and a no-go when warm?" What increases resistance in an electrical circuit? Length of the conductor, wire cross-section (gage), type of material in the conductor (copper, aluminum), temperature. Heat soaking the engine could be causing the electrical resistance to increase in the starting circuit. Deja va: I had the same issue on my 327. You say you have "heavy duty" battery cables.....just what gage are they? Got myself some 2 gage cables, positive AND negative: problem solved. Have you qualified all your power AND ground circuits? Wire brushed all those connection points? I know it's already been mentioned earlier in this thread regarding cables but have you REALLY confirmed those cables/connections? Do yourself/us a favor and check...Deja vu all over again.
