/6 to V8 questions

Thanks for the guidance. I'm guessing my car, while very nice, is only worth about $4500 as it sits. Since the body is excellent without any rust, it looks cost effective to modify what I have as opposed to selling and buying again. Correct assessment? I'm not following the lingo for the rear end (long legged) or the engine mounts (spool mount V8). Could someone school me on those. I found a 318/904 car local on CL. It's a runner too. Do all V8 cars have disc brakes?