So, I just got a nice 1984 F150 with a 351W. It's my first truck. I was hoping someone could compare the differences between the 351M and 351W. This is probably one of the most basic questions, but gimme some help. Thanks a lot.

 

351w is in the same family as the 302 thus it has tons of aftermarket support, almost as good as a sbc, it is the best of the 351's ford made, the modified the cleaveland and the windsor, it is a rev happy motor can be built to make tons of hp, the 351m on the other hand is strictly a truck engine, marginal torque and hp, but will pull anything like rock and stuff that sucks anyway i rather go fast, very strong and bulletproof tho, detuned and i mean detuned to the hilt to meet emissions requirments, poor breathing charecteristics mostly due to 2v induction, and very low compression all these combined to a very weak but can be built to produce power on the cheap ( what cant ?) most of the 351m running around today dont hold more than 15-20lbs of oil pressure warm, well i probably didnt help much and im sure someone is going to jump all over me for this post but oh well