hey guys, I know this may seem like a foolish question, but here goes: there is a 4 speed transmission for sale in my area, but the bellhousing currently on it is for a 390. I have a transmission currently on my motor (300 I6), can I swap the bell housings to make it fit my motor? Or are they transmission specific? Thanks, Michael
The four speed transmissions Ford used over the years had two bolt patterns. Some gear box castings had both. If you are looking to buy a trans and a bell, be sure both are compatible. Then, mock it up with no clutch and peek inside with a mirror to check length. Some transmissions need the input shortened about 3/8 of an inch. If all this begins to add up to serious money, think about stepping up to a five speed. There is nothing more satisfying than getting up to 65 and shifting one more time and watch the tach fall to 2200.
If the trans was used behind an 390 then the pilot bearing area on the front of the input shaft will be too short, may be able to find a pilot bushing that sticks out of the crank by 3/8" to make up the difference....
Thanks guys, so the gist is that I should wait to find a trans that was used behind a 300 if I don't want to do an inordinate amount of extra work to get it to bolt up?
Champrod That trans should be either a T-10 or Toploader 4 speed. If it's in reasonable condition, and it's cheap? BUY IT. Cheap would be under $5oo. They are great trans and quite valuable. You won't be sorry
Jimmy2car: The 4 speed is out of a 1969 f100 4x4, with the transfer case included, it is $300, but if the input shaft is going to be too short, then is it even worth it/ possible to find a pilot bearing that will work?
A bronze pilot bearing is pretty easy to make if you have a friend with a lathe. Or a machine shop that will do such a small job.
The 390 bellhousing won't fit your 300 six, but the transmission may fit your bellhousing if it's for a manual. I'm assuming you have a three-speed now, which will be a 'car pattern'. The truck-only gearboxes may or may not have that same pattern, you'll have to check. But that 4WD truck four-speed will be a 'granny low' box, pretty much worthless as a street transmission. The short pilot shaft when using a FE trans with any other Ford motor is a common problem. The fix is getting a steel bearing in place of the bronze bushing. I'm pretty sure the 300 uses the same pilot bushing as a SBF V8, a steel sealed bearing works. A NTN 6003 LLBC3/5K is one number, most any bearing place will have this or can cross into whatever they sell. This is 41mm (OD) x 14mm (ID) x 12.7mm (thickness). If the six is different, they can very probably come up with something that fits.