No go on the pusher. If you go electric, use a puller.
Most of the people making comments have 67-69 cars. The issue is less critical. The 65-66 cars have a dinky 17 radiator. MustangMatt you need to throw the 2 row in the garbage can.
There are several people here I'm sure with 65-66 cars that have cut their core supports and installed the 67-68 20" radiators with great success.
We were the first that I'm aware of that just welded in the 67-68 core support and installed the 67-68 24" griffin alum with saddle brackets and use a dual puller flex-a-lite slimline to cool it. The temp gauge doesn't move... We have a rapped out 302 SC with AC. There's no substitue for a bigger radiator!
I'm sorry I disagree. I've used them in a pusher config and have not had any success. The mechanical was actually better than a pusher... It works ok when you stop, but in blocks the air flow when you're moving down the road.