Howdy folks, after a few year absence I find myself coming back for more.

My dad has a 77 f250 4wd 4sp with a 351m, power steering power brakes. The truck is in fairly nice shape but the 351m is getting fairly tired. We have a line on a rebuilt 390 that a friend built for a project galaxy but he went another direction. Theoretically this should be an easy swap right? Change the motor mounts and a trans adaptor kit? I was thinking it can't be this easy, what am I missing. I mainly deal with new trucks or old jeep trucks. Please point me in the right direction folks.

 

It's the little things that make a swap like this a question mark.

First, you will not need an adapter for the trans, just an FE truck bell. The bell to trans pattern will be the Ford "butterfly" rectangular pattern, in place since about 1965.

Cooling, exhaust, accessory mounts, linkages and perhaps some clearance issues as the FE is a bit longer than the 351m.

FWIW, I'd rebuild the 351M into a proper 400 with some compression and a decent cam. No need to go nuts, and all your money goes into the engine, not the nickel and dime small stuff. jmo, ymmv.

 

Is the truck a highboy? If yes, it is a stupid simple swap.

 

yes it is a highboy, thanks for the replies guys...my dad used to have these trucks new on the ranch back in the 70's and absolutely hates 335 series. He claimed FE may burn oil its whole life but would last another 30 to 40k.

 

You just need the motor mounts, motor mount towers, and bell housing out of a '67 to '76 highboy with an FE and bolt it all in.