Originally Posted by onebadmerc
This is wrong, the 351M/400 engine mounts and towers are not the same. Ask me how I know, I replaced the 400 in my 78 F250 with a 460. The 351M/400 towers and engine mounts dont even resemble the 460 engine towers and mounts.
Don't take my word for it.
There's a company called L&L Products that specializes in 460 swaps. They offer parts to put a 460 into various years and models of Ford pickups and Broncos.
The kit they offer for the '78-'79 F-250 4x4 does not come with towers, just the rubber mounts that bolt to the engine and the tower. The kit for the '73-'77 F-250 4x4 comes with towers as well as the rubber mounts.
Both kits come with a bunch of other parts such as a clutch, flywheel, rear sump oil pan, headers, etc.
I have no affiliation with L&L, and I have no idea how many of these kits they've sold over the years, but I would think if the '78-'79 towers had to be replaced, they'd know it and would include the replacements in their kits.