[mustangman65_79]

I would more lean to the conetions to the block. U may be running a connetion that is fine when cold, but when those wire heat up, as I've noticed, they seem to lose power, more restaince some how. Before u go and buy another starter, save some money by either cleaning your connections, or buying some 2-4 guage wires. Make sure they have good, clean points.

I was having the same ploblem with my car a couple of weeks ago, and i thought I trouble shot it down to a bad starter. When it was cold, everything was fine, but after it was warm, it seemed like the starter was taking too much juice out of the battery. I tried one last thing before going to get the stater, and it fixed it. I found out that my battery connections were lose, but not bad enough to see or cause any thing else. They were only lose by a little bit, but it was enough to cause a hard crank when it was warm. So now it works like new.

So, here;s what I'd do

#1 check batt connections
#2 check ground, then power connections
#3 buy bigger 2-4 guage power and ground wires
If nothing else, then #4 buy a new, not rebuilt starter.