the interior would be gutted in favor for a cage and a set of sparcos, so, the interior is no issues, and rust can be taken car of, as long as i can get patch panels or make them easily.
IS this going to be a street car or a track car? Do NOT put a cage in a street car. Just don't. It's dangerous.
My suggestion is to buy something normal for $500 that's butt-simple and ugly, but is solid and runs every time you turn the key. Drive that for what you actually need a car for. If you want a project to tackle with your father,
then buy the MG, but do NOT buy the MG thinking it will be a great daily driver after you spend a little time on it.
It's been sitting, not running, for longer than you've been alive. At a minimum it's going to need a complete teardown of the engine, transmission, and braking system. MGB parts are not rare, and are being reproed or re-engineered by specialty shops every day... but it's NEVER going to be like running down to your local NAPA and picking up a set of valve lifters for a small-block Chevy. It's going to be swap meet finds and internet networking and eBay and luck.
From a few pictures it looks like a solid start to a project... but there's a
reason it's being billed as a parts car.
Before you even
think about buying this, find an MGB forum and ask the same questions to a bunch of dedicated guys who have been there and done that more than once. Don't ask us here - with a few exceptions, we're shade tree at best, and not MG experts.
[edit] Oh, and go read Giles's post again. Now read it
again. Really. And if you're considering an engine swap using a wide variety of trendy motors, I'm less convinced than ever that you understand what you're getting into. If you think $5k will get that thing running with a Jaguar - or worse, a Nissan engine - you are deeply mistaken unless your father is Smokey Yunick. And this is speaking as the son of a man who could fabricate anything necessary in his own machine shop.