How Can I Make A 351 Windsor Fit In My 66 Mustang? The Headers Won't Fit Between The Shock Towers.

Ugg one more year older and you wouldn't have this problem. This is common problem as 351 is very tight for a 64-66. I would never cut on the shock towers unless you bring the stability back in through welding. Both Hooker and Hedman make headers for this specific swap, I think that will be you best bet, though not cheep.

-by the way I have a 58 ford f100 with a 289

Go through jegs and get the headmen headers for it they fit but its goin to be a tight fit I did the swap in my 66 or you could get in contact with hooker and they have them too