Hello Im new here maybe you can give me some good advice. I have a 69 with a 383 stroker motor I need to replace the radiator my question is im thinking of putting a 396 over the winter so I want to get a good radiator that will work now with the small block and still not have to replace it when I change over to the big block any suggestions will be very helpful thank you

 

I have a Champion 3 core that is rated to cool 600 HP. it cools my 500+ sb without any problems
I hope you realize that going from sb to bb will require a lot of changes and parts

 

Welcome, OS69,
As F/Tire suggests, alot will have to be changed:
Frame mounts for engine mounting,
Trans crossmember to match above
Heater core and fan cover, if heater will be used
Accessory bracketry,
Throttle linkage, maybe
While you're at it, change body bushings to Moroso solid bushings use antiseize on threads.