i have a 79 ford f150 4x4 and the 400 is pretty tired so i am puting a 351 in it i think i have most of the stuff for it like bell housing and stuff but one thing i dont know is what to do about motor mounts i dont know if the towers are different or if anyone makes the the mounts any info would be apreciated  

351W uses a different block than 400. If you could find a 351M with is based on same block as 351C and 400 it would pretty much bolt right in. The 351 M was built from 75 to 79. Also for what it is worth, the M is a sturdier motor as it is a taller heavier block with longer rods and bigger bearings.  

Snoman's right, 351M is a better motor than 400 and 351W. Altough weren't built for a long amount of time they're preaty pleantiful. You can find alot that's redeamable at a junkyard, look in 75 to 79 trucks and Broncos 78 and 79.  

The 351M is basically a 400 tall deck block with a 351W style crank with longer rods for taller deck height and 351C heads. If I was to use a 351 in a 4x4 truck, the M would be one I would use. (also for what it is worth you can easily stroke a 351M out to a 400 with a 400 crank and rods.  

i already have the windsor so thats what im using i just need to find out about the motor mounts  

Well being that the 351 W is based on a 302 block with a taller deck height to accommodate the longer stroke you "might" try 302 mounts.  

do you know where i might find some  

my first place to look for new mounts would be LMC  

I would look at Jeffs Bronco Graveyard. They deal strictly in Ford and have a lot of great stuff, including engine swap parts.