Starter heat soak
Have you had this problem from a recent change of something? I had a rebuilt 440 and full headers and had heat soak starter problems till I had some miles on the motor. I then removed the headers and went to Hi po exhaust manifolds and problem went away for good. I then put a gen2 hemi in the car and went with repro exhaust manifolds and never had a heat soak problem with them. I don't race so I give up the 20-30 HP loss with the manifolds but have other benefits, long lasting less heat and noise.