Gents,
Just an FYI.
With my recent 428 build and once I got her running I had an issue where, due to heat soak, the engine wouldn't crank when hot, not fast enough to start anyway. I was using a re-manufactured stock starter with Sanderson shorty headers, there is around 3 to 4 mm clearance between the two. No room for a heat shield. I read on here and elsewhere that heat wrap could help so I tried it out, this is what I found.
Prior to heat wrap I would have to wait 15 minutes with the bonnet open on a 30degC day for the starter to be cool enough to spin the motor. Check with a IR temp gun straight after a drive I was seeing around 250degC at the starter housing.
After heat wrap, in similar weather I only had to wait 4 minutes with the bonnet closed to be able to crank. IR temp gun straight after a drive was showing around 150degC at the starter housing.
Conclusion, IMO, heat wrap helps but in my case did not help enough. I bit the bullet and bought a clockable "high torque" reduction drive starter. No issues starting now, hot or cold...