Before you say anything. I live in CA and have strict smog laws to deal with and can't do a v8 swap. With that said. I have heared that a 2004 Mustang 3.9 block will swap into a 1997 f150 with a 4.2 ( slight mod to knock sensor ) Any thoughts on this swap??? The current 4.2 is worn out and knocks. I dont want to spend the money on rebuild. Low miles 3.9's are cheap. Thanks Marc

 

4.2 has more torque.

Also, try v6power.com or 3.7mustang.com

They've been swapping 3.8/3.9 (same motor) for years.

 

Thanks for the links.