IR temp gun is around $30 at Harbor Freight.
IIRC, your radiator opening is only 22"
38 degrees of timing seems a lot for a 4" stroker motor. What is your cam specs and compression?
I'm running a comp XE274 cam, 9.7:1, quench, and 31 degrees of timing. 4 core champion, home made shroud, 15" 7 blade fan, jag fan clutch.