I recently picked up a 85 F150 with a 351, knocking like crazy. This is my first Ford, could someone tell me if the tranny needs to be changed if I go to put in a straight 6(300)? And/or if there is anything else that needs to be changed to do a swap? Thanks.

 

Certainly, I'm no expert, however, I just went through a similar swap in July, but from a 302 efi to 300-6 carb conversion. I would assume both your motors are carbed. I found that tranny will bolt up to 351w, 302, and 300-6 but flywheel must be for a 300-6 due to balancing. Also, frame motor mounts as well as the rubberized motor mounts on the engine are different. So are the radiator hose connections (they are opposite sides). I found a dead (300-6) soldier for free at a garage and had a radiator shop switch the plastic side tanks for about $40. Of course, exhaust and the mounts for the accessories are different-alt, power steering, etc (starter should bolt right up, though). But depending on the year of the 300-6, I swapped the entire accessory mounting brackets to retrofit my 86 to a 79 setup, which I'm a little more familar with anyway. And after I was all done...it actually worked quite well. In my case, I found the 300-6 to pull much, much better than the 302v8 but I doubt it'll do better than a good 351. Someone else here will probably have much more accurate insight as to the performance diffence between the two but I could'nt be happier with my results. Good luck on your project.

 

>I recently picked up a 85
>F150 with a 351, knocking
>like crazy. This is my
>first Ford, could someone tell
>me if the tranny needs
>to be changed if I
>go to put in a
>straight 6(300)? And/or if there
>is anything else that needs
>to be changed to do
>a swap? Thanks.

Roscoe pretty much hit the nail on the head with the changes needed. If you have to buy all the parts for the changeover, it may be just as economical to rebuild the 351. It all depends on what you want to do with it. If you were going to be doing much heavy towing, I would stick with the 351. More cubes=more torque.

DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, T-18 but looking for a ZF. 3.55's.

 

The swap info is correct on all the accessories, etc. I would tend to keep the V-8 radiator and run universal type hoses to the opposite side on your 300. The V-8 radiator is larger (has more tubes) and should be more efficient. I also had difficutly in figuring out my vacuum systems and smog equipment hookups, but after studying diagrams and trying to read the function of the vacuum switches, I was able to eliminate a lot of stuff and still stay smog legal.

'82 F150 2WD w/351W (orig 300 I6)
Slik