i just meet this guy with a 73 ford with a 351m that was taking out of a 78 in place of the 390 that came in it. he's had the truck awhile and has never had the tranny bolted down and it finally broke one of the motor mounts. switched the motor mount out last night and i'm trying to figure the best solution for the tranny. the tranny is a auto also. i'm not sure if the tranny was swapped with the engine are is a 73. by the look of the mount bolted to it i would say that it's the 73 tranny


the problems is obvuois that the tranny flopping around caused the mount to break. the tranny is about 2'' forward of the mounting holes on the cross member, i'm guessing that the 351m has a shorter block than the 390 does.

did the 78 have a different style crossmember than the 73?

i can't just move the crossmember forward to match the holes on the tranny cause the control arms are bolted to crossmember and the frame. it could happen but i would envolve a some new brackets and such welded on.

were the frames basically the same for a 73 and 78?

his solution is i just weld the plate coming of the tranny bushing to the crossmember. i'm not really into that as much as i am trying to figure a way to do it right.

any info you can give would be greatly appreciated.

Your post is a little hard to follow, but let me give this a shot. You are takeing a 390 out and putting a 351m in. Here are the problems that I know of with this. The frame mounts are diffrent. The bellhousings are diffrent. Are you working with the 78 or the 73? If you are working with the 78 the diffrent frame mounts that were never chaged would accout for the FE set to no tline up with crossmember.


There is a large number of things that could be wrong. Get a little more details and I'm sure one on the board can hook you up.

thanks for the reply and it's hard to follow cause i rely don't have the details about the swap like whether or not the tranny was swapped with the engine and what not. i'll have to regroup and post later when i got all the info. thanks again. chris

i could see why you would want to swap a 390(cc) for a 351 CI(cubic inch) big power increase, you know 390 cubic centeters dose not produce the real power.

but in all seriousness why take out a perfectly good very powerfull 390 for a power robbed 351m. the 351m is the cali smog motor, they suck! put in the C or the W.

it's not my rig and the conversion has been done already i'm just coming in after the fact trying to fix some fawk ups. probaly just going to make a cross member for the t-case and call it a day. :usa:

flip the crossmember around. That is if someone put it in backwards.

Originally posted by f150ed
i could see why you would want to swap a 390(cc) for a 351 CI(cubic inch) big power increase, you know 390 cubic centeters dose not produce the real power.




Damn you beat me to it... :D

Originally posted by emsoffroad
flip the crossmember around. That is if someone put it in backwards.

i'm not a ford guru and i'm not laying under the thang at the time so if i remeber correctly, i don't think you can put it in backwars cause the conttol arms mount to the crossmember. i'll check though.

The radius arms go to a mount that gets bolted to the crossmember as well as the frame.

The Crossmember being in backwards is a real long shot.

Also make sure the tranny mount is not in backwards as well, you can put them in either way. It should be the big square one with 4 sloted holes in it.