My last GTO with this Very same motor, and radiator, was rock solid for heat, it stayed at 200, sitting at iddle in 100 degree heat for 40 minutes or doing 80 on the freeway.
But the same combo in this Goat overheats at idle in gear and if I go ver 80 for long periods of time, part of that has to be the 3 speed auto and being at a way higher RPM, then the old goat was with the six speed. I do not think the tranyy is doing it cause I am using an exsternal cooler for it.
I think part may be the fan, about an inch out of the shroud.
If I rev it or put it in park is does not ever heat.
Hmmm anoying and I don't have the cash right now for an aluminum radiator, I am hoping the fan Spacer will help I just need to get it in.