ok, I'm a total flathead virgin so I need some help. I'm gathering parts for the next project. I've got a 38 24 stud flatty out of a truck. Torque tube trans attached. I also have an 8BA and another truck trans.. this one is open drive though.. My question: what can I do too hook either one of these motors to a 40 Ford pickemup rearend??? I've looked into the 39 car 3 speeds and I don't have the $700 some people are askin for those! I would like to keep the torque tube. The plan is to use the earlier engine unless it's too far gone... TIA
If your 38 ranny is a 3 speed use it. You can change the open drive to closed or convert the torque tube rear to open. If you want to cange the tranny, I would be more than happy to trade you.
Killer: If '39's are too much in your area, look for a '37-'38 case and get a complete side shift '42 to '48 car trans and just swap the gears into it (that's what I'm doing). And if you really want to get fancy, use the truck case ('39 and up)which is stronger thru the bottom. Just make sure the tower forks (towers with double detents for more positive shifting are the hot setup!) match the collars on the main drive gear. Check out av8 and Vern Tardel's book - it describes the whole process in detail! Regards, Dave.
Nothing really wrong with the 38 trans, just the synchros aren't as nice as a 39 or later trans. The torque tube will bolt directly up to it so use it. The later truck trans with the open drive should have the better synchros, and I think you can transfer the output from the early trans to the later, but have never done this. The cases are probably the same pretty much dimensionally, but the later one will be stronger. The later one might have a bad ratio though (more granny gears) so check that out. alchemy
if you want to use open drive and the close drive torque tube trani i believe you can use --lacking technicall term here- rear tailshaft ish? part of a 40s open drive truck trani and bolt it onto the closed drive trani to convert it to open drive summary closed drive + truck part= open drive could be wrong but im thinking thats right tim
What AV8 Dave said. If you should decide to go with open drive it's possible to adapt the tailshaft from a '49 Ford 3-speed but what's the point when you could just use an SROD or T-5? Also, there's nothing wrong with the '40-'48 side-shift box and a column shifter.
Open drive lines are the Devil. I'd say use the '38 transmission behind either motor. Seems like you already have all of the bits to do it.
The best 39 gear box is 39-49 pickup case with ´the innard's from a 42-48 gear box. The 38 case should work good with 42-48 innards to, and make a nice 39 box. The 37-38 case have 78 cast into left lower rear corner. I have a scanned gearbox article i could mail you if you want. Or even better go out and by How to build a traditional Ford hot rod, if you are into flathead's this book is a MUST to have.
The closed drive output shaft will not accept the open drive gears, the helix is a different pitch, and the low gear slider binds up. It's a shame too, because the gear ratios are more like a Zephyr gearset, than a Ford passenger gearset. The good cases have a 78 cast into the rear face just under the output shaft. A 38 trans is likely a 78 case, but doesn't have the better syncro. FWIW, Ford changed the syncro about every two years, and not all of them interchange. There is no shift fork for an angle tower top that fits the later, 39 and up, gears. You can modify a later fork to fit the angle tower top. The vertical tower tops came both ways, small fork, or large fork, and they will interchange. Late top small forks are not available new, so you have to scrounge one. Most of the rest of the parts are available new.
Charlie: HAMBChop... yes. You guys confuse the hell outta me... I WANT THE TORQUE TUBE! NO OPEN DRIVELINE!!!! Please email the gearbox article... addy is in my profile. Tellin me to buy Mikes book is funny on so many levels..
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