Engine cooling issues on a blown 302

[GeorgeW]

First attempt at a post with a picture.
I'm trying to find a water pump pulley in the 5 1/4" range .
trying to cool my little pony.
Blown 302 30% under driven 671 (2) Holley 750's
I haven't touched it in over 20 years so I'm sure technology has changed .
Ron Davis radiator. They recommend trying to find a 5.25 water pump pulley
Any suggestions?

 

[WORTH]

when is it overheating? idle, around town,highway, drag strip? What temp is she running?