Stock Starter issue on High compession Engine

the engine was rebuild from a Cobra Jet Q code (8:1 static i guess) with open chamber heads 74.x cc to a higher compression engine. Static now app 10.4 , dynamic app 8.
The Starter is the original from dimension the "big monster starter". Starter is in top shape with new brushes and polished collector.

When Enginge cold no problem to start, starter cranks good, no Fail!

When Engine hot starter dose not crank, goes on block. (engine stopped at intersection as carb still in adjustment process..needed to push the CAT Big Grin)
1) Bat is top end
2) power cable is the old black one with good connection to starter and on Bat side (I will def re-tighten)
3) ground is provided via direct chassis connection (10" from starter to chassis bars)
4) starter sits on the 2 screws, tightened ..

what is your thought..hight torque starter? recommendations? Issues?

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