I was wondering if a 1978 Caprice is a B Body or G body, can somebody clear me this?
Thanks.

I was wondering if a 1978 Caprice is a B Body or G body, can somebody clear me this?
Thanks.

B-body. G-body is Monte Carlo.

All full-size RWD Chevrolets are B-body.

It is a B-body. The Caprice has always been a B-body and the full-size Chevrolets have always been a B-body since 1959. Here's the short of it:

The full-size Chevrolet started out as the A-body until this was replaced (really just renamed) by the B-body in 1959. The full-size Chevrolet continued to use the B-body style until its demise after 1996.