A,
Correct, the crossmembers work fine with the 250. I agree with GMCpanel that adapting the sending unit won't be hard. If it's running fine, I wouldn't be in a hurry to lose the integral head if it has one. There are always a few cherries even in a lemon design. Swapping the head later is easy if need be.
My stock rad works just fine with an electric pusher fan in front. I run 180-185 consistently and have only seen 190-195 tops. I use a 4lb cap.
