My 71 may need a new radiator. Its a base engine 4spd with air cond. What size copper rad belongs in this beast. It does not have an expansion tank nor was it supposed to I think. Can I put a larger one in?

I wouldn't think that a larger radiator would be a problem. After all you want to exchange as much heat as possible. I may be wrong, but I thought that all C3's had expansion tanks. My base 300 hp/350 ci has one anyway.

Henry,
If you are going to put in a new radiator, have you considered one of the aluminum ones by BCool or or one of the other third party shops? They are a little bit more expensive but from what I understand, well worth it. They also offer electric fans that attach to the radiator to aid in cooling.

We have a 1969 4 sp Vette. When I installed a 383 motor in the Vette it would run hot in traffic.I installed a BeCool radiator. Summit #BCI60029.I had to do a bit of trimming but the results were awesome.I have not seen temperatures over 195. They also make a smaller radiator that would probably be a drop in for a small block. Jim Wagner

Hi
No, not all C3 had expansion tanks.
My 68 big block for example has none and never had.
But, I agree, the 71 should have it.
The radiator should be a 31x19 inch, and yes, a alu radiator ( with 2 rows of 1 inch cooling ribs ) will outperform any original copper one.
I'm in process of installing a SUMMIT ( NORTHERN ) universal racing alu radiator. ( 29x19 inch for 68 only , the 31x19 will not fit into 68 )
The universal units are very cheap ( 180 $ ) against the unique Vette radiators, which cost 500 $ +, but they do need a bit of trimming, new mounts and new hoses ( or rewelding the outlets ).

Good luck Gunther