78 Arrow...

Welcome! How big of tires? I like how those Arrows look pro street. I’m sure a big block stroker would go nice in there. I don’t know what sort of model specific performance those cars would have, especially since it is a mitsubishi and it sounds like you are looking to stuff a big v8 drivetrain in. I would figure out what motor/trans combo you are looking to use, slap some mounts on it, I prefer spool type, and dry fit again and again until you find a good location to mount the frame sides of the mounts. Decide what rear, buy rims and tires, measure, measure, measure. Tire size will decide how much you need to cut off of where. Wheel wells, floor, quarter, all depends on what you want to stuff in there. I look forward to seeing what you do with your car!