You might find various carburetors on an MGA. For that discussion read "Alternate Carburetors". Otherwise all MGA (except the Twin Cam) originally had the same twin SU H4 carburetors (with a couple different numbers for various fuel jets). You might also find that the original cast iron exhaust manifold has been replaced by tubular headers, which is no great crime, but it can be a little noisier, and it may not improve performance noticeably unless it is done in conjunction with some upgrading of the cylinder head and carburetors.