Re: New rebuild ,barely turns ??
If it makes a difference, my newly rebuilt motor (never ran, new everything, bottom end, crank turned, bearings...) was very difficult to turn over, especially after setting the valves. Even with the rockers loose, it was still difficult, I'm not saying there isn't a problem, but it's probably nothing to worry about.
After turning it over after 6,000mi by hand, it seemed way easier.
The only Mustang I'd ever own is a Fender.
'68 333" Camaro
'14 5.0 Mustang