The only overheating trouble I've had with these engines was the stroker I built with 4.00 bore (.125 oversize) and the cooling jacket filled about 1/3 the way up with Hardblok. Never spewed coolant but clearly ran hot. My latest engine is very similar but with 3.935 (.060) bore, no Hardblok and does not have the overheating problem. I attribute the overheating to the thin cylinder walls. Not sure if that's the true cause or not. An anecdote only, may not apply to your situation.
