I have a 83 F250 with a siezed 351w,what options do I have in swaping out the motor with little modifications invovled.Can I use only a 351w engine and what years did they change/modify the 351w motor.A local guy has an 86 that may have a 351 in it.Whats the diff between the 351w and the 351m?thnxs

 

If you have the dipstick in the oil pan, you can use any 351w from a car or truck from the 70's up to the early 90's. You just have to swap the oil pan if you get one out of a car.

You don't want a 351m. It's a totally different engine and won't fit your tranny.

 

If the 86 does have a 351 it is a Windsor, the last 351m/400 were used in 1982. I did the same swap a few years ago with my 83, using a 93 EFI engine. All you need to do is pull the EFI intake manifold off and put your old one on. The fuel injected engines also used electric fuel pumps but it's very easy to switch to a mechanical pump. The EFI engines have a small plate covering the hole used for the mechanical pumps, just pull that off and bolt the old pump on. Use the distributor from your 83, and like Dave said swap oil pans if you need to.

 

On the efi 302 I swapped, I had to change the whole timing cover to get the fuel pump mount, and also had to change the cam eccentric to a 2 piece job.

I then went ahead and used the older style waterpump and fan, since the efi engine used a serpentine belt setup.

 

Every EFI timing cover I've worked on has been a cast piece that has the provision for the mechanical fuel pump, but needs to be machined before it's usable. You need to change the timing cover.

 

thanks guys....