493 hard to start when warm

I have a 440 stroked to a 493 that is 10.5 to 1 compression and running a comp solid roller cam. It has an MSD distributor, ignition system and MSD high torque starter. I believe timing is set at 36 or 38 degrees and the distributor is locked out. The motor runs great and hasn't had any issues except for not wanting to start when it is warm. If the car has been sitting the motor will fire up as soon as you hit the key. If the car is warm, it will half way turn over and then nothing. If I keep hitting the key, it might take 3-4 times and then the motor will finally turnover and fire right up. I thought the it might be a ground issue at first as the battery is in the trunk, but I ran a new heavy duty cable from the battery to the starter and still am having the same issue. AS the motor is only 10.5 to 1 I didn't think this is a compression issue, but it seems like it. Thoughts?