None, that's a horrendously bad idea. The engine will not fit without major cutting and welding. The steering shaft will not clear anything wider than a 302. Everything would have to be custom made to fit... This will almost certainly result in the end of the 1978 Mustang that you're working on. Even normal 302 headers don't fit in a Mustang II. The car was originally not even made to fit anything other than a 4 cylinder and small v6. Ford had to revise the whole front end to shoehorn a 302 in the car in 1975.