How Hard Is it to swap a 351 to a 390

[Foul Al]

I have a 79 bronco how hard is it to switch the 351m to a 390? i Know you have to change tailshafts engine mounts and linkage. what about the electrical connections. i have alot of questions can u help.

hey there yoder, i have done this exact swap your thinking of doind and its not that bad. what you have to look for is the shaft length on the tranny. if i remember correctly when i did that swap the tranny shaft had to be a little longer than the one from the 390's tranny shaft. also the motor mounts only moved foreward 1 hole. so you have to make the rear hole on the mount go to the front hole on the frame and drill a new front hole in the frame. theres plenty of room to put nut behind that bolt. all the other electrical stuff bolts up. i was really happy with the results of my swap!! massive power upgrade!

 

[Johnny Reb]

hey there yoder, i have done this exact swap your thinking of doind and its not that bad. what you have to look for is the shaft length on the tranny. if i remember correctly when i did that swap the tranny shaft had to be a little longer than the one from the 390's tranny shaft. also the motor mounts only moved foreward 1 hole. so you have to make the rear hole on the mount go to the front hole on the frame and drill a new front hole in the frame. theres plenty of room to put nut behind that bolt. all the other electrical stuff bolts up. i was really happy with the results of my swap!! massive power upgrade!

When I put my 390 in my 78 broncp. The transmission was already in. I did not have to do anything with my drive shaft.Youder. I will go out and take some pictures of my installed job. I hope the pipctures comes out good and then I will try and get the poste on her. The job is not intimidateing at all. It was the easiets jopb for me. Alot easier then puting a 428 down into my 66 fairlane---not much engine compartment-but the bronco has plenty of room to work arond. Good luck. You live close to West Va? **** I,ll come and help you set it in.

 

[Johnny Reb]

quote name='Foul Al' date='Mar 27 2009, 08:33 AM' post='91605']

hey there yoder, i have done this exact swap your thinking of doind and its not that bad. what you have to look for is the shaft length on the tranny. if i remember correctly when i did that swap the tranny shaft had to be a little longer than the one from the 390's tranny shaft. also the motor mounts only moved foreward 1 hole. so you have to make the rear hole on the mount go to the front hole on the frame and drill a new front hole in the frame. theres plenty of room to put nut behind that bolt. all the other electrical stuff bolts up. i was really happy with the results of my swap!! massive power upgrade!

The 390 -I took it out of a 74 king cab . Now I did not have to do anything to the transmission. I left the 4 speed in the 78 bronco and the 390 bell houseing and everuthing bolted up. And the bolt hole where the engine mount went in. I had to drill AVOVE -THE ORIGINAL 78 BRONCO FRAME MOUNT,. After that everything went in place. I also had gotten a ckuth rod assembly(from the frame to the motor block) out of a 76 pick-up. I will try and have my friend take some pictures for me with her digital camera. Good luck.Oh I also use the 390 motor mouonts. The radiator hoses are also on the same side as the 351. ,but I went ahead and got a 4 row radiator(cost was close to $500 ) to make sure the motor never over heated.I am p[lanning on getting it on the road this summer. Women--they take alot of money-----I just might let her go and work on my bronco.(haha)

 

[Foul Al]

quote name='Foul Al' date='Mar 27 2009, 08:33 AM' post='91605']hey there yoder, i have done this exact swap your thinking of doind and its not that bad. what you have to look for is the shaft length on the tranny. if i remember correctly when i did that swap the tranny shaft had to be a little longer than the one from the 390's tranny shaft. also the motor mounts only moved foreward 1 hole. so you have to make the rear hole on the mount go to the front hole on the frame and drill a new front hole in the frame. theres plenty of room to put nut behind that bolt. all the other electrical stuff bolts up. i was really happy with the results of my swap!! massive power upgrade!

The 390 -I took it out of a 74 king cab . Now I did not have to do anything to the transmission. I left the 4 speed in the 78 bronco and the 390 bell houseing and everuthing bolted up. And the bolt hole where the engine mount went in. I had to drill AVOVE -THE ORIGINAL 78 BRONCO FRAME MOUNT,. After that everything went in place. I also had gotten a ckuth rod assembly(from the frame to the motor block) out of a 76 pick-up. I will try and have my friend take some pictures for me with her digital camera. Good luck.Oh I also use the 390 motor mouonts. The radiator hoses are also on the same side as the 351. ,but I went ahead and got a 4 row radiator(cost was close to $500 ) to make sure the motor never over heated.I am p[lanning on getting it on the road this summer. Women--they take alot of money-----I just might let her go and work on my bronco.(haha)

hey jonyreb, if you still have the reciept for the rad. take it back and buy mine! i have a slightly used one that will work perfectly! if your interested get in touch with me by p.m. i will let it go for $300.00 shipped. let me know what you want to do.

 

[Johnny Reb]

hey jonyreb, if you still have the reciept for the rad. take it back and buy mine! i have a slightly used one that will work perfectly! if your interested get in touch with me by p.m. i will let it go for $300.00 shipped. let me know what you want to do.

Well Al, I already bought one(and I probably paid too much-they over charged me on some rotors and hubs too) but hear is a guy on the sight looking for a 4 row radiator. You and him might work out something. Hear is his e-mail [email protected] and his name on hear is rhett. Good luck to both of you.Thanks anyway