Originally Posted by My03fx4
Theres no way that tranny will hold up to either of those engines.
Sure it will. Considering that Ford put the M5R2 behind the 351 in Broncos and F150's. There are also guys who run an easy 500 horse through them in their T-Birds. The only difference between a T-bird M5R2 and a F150 M5R2 is the synchros are a little different.
Now a 400hp seems a little high to me but Ford ran the engine for nearly 50 years so I could see that level of performance being out there.