There are many variables for engine fit in different frames. My 460 is wide and will interfear with the frame on some kits. One thing for sure is to either cut a stock
oil pan down to 7" deep or get an aftermarket one only 7" deep,doesn't matter if it's big or small block, 7" is the limit. [one day you'll thank me for that tip] Same thing with an intake manifold, get one that is short to start with or be ready to rivit on a larger scoop. You can mock up an engine out of cardboard or buy a junkyard wreck engine for $50 ; from
oil pan to carb and air filter and trial fit it in the frame/body before you spend big bucks for an engine. Good Luck,
Perry.