The old standby 302 5.0L or 351 5.8L pushrod Ford Small block has been around forever and for good reason. Small cubes mean quick and high revving with a high torque curve that made the Mustang V8 a stoplight performer and drag strip warrior. Mustang budget short block is a great choice if your pony has lost some of it's stride or a completely built Ford Racing Crate motor would work just as well between the frame rails of your Mustang driver or racer. Lot's of short blocks, long blocks and crate engines for your Mustang pleasure.
Testimonial: Coyote swap parts a step above the rest.
Late Model has made choosing the right parts for my coyote swap fox body much easier. With a dedicated section for this type of build and constantly updated with the latest parts it was a clear choice for me. They even did they're own swap with instructional videos. Thanks Late model!