Hello All
I got a 67 F800 that was a fire truck, turned into a service truck.
My old 391 is just wore out with 21000 hard miles on it. I have a 5 speed direct clark trans model 305-V.
I have a 460 ready to rebuild but i need a trans to go behind it. I want a 5 speed over drive, or anything with an overdrive.
My plan is to get a front motor mount off of a 429 truck engine and a bellhousing to go with it, that will make building motor mounts so much easier.
But i dont have any idea or clue on how to go about looking for a transmission. Do you guys have an idea on a trans to look for, like model number and application, guess im going to need all the clutch parts and flywheel stuff so i can find a starter to work also.

My other option is to just rebuild my 391 and leave the trans alone, for a $1000 i can have a different ring and pinoin gear set built.

Right now im at 60 mph at 3500 rpms with 42 inch tall tires. I dont think i can get enough power out of the 391. I pull a grain trailer and gross about 50000 lbs . I need to slow the engine down and still pick up some mph.
Also i am planing on swithing to propane, $1.80 compared to $3.15 gas at 3.2mpg is now good.

Any help would be great, Thanks alot Guys

 

To go behind a 460 you can get a ZF 5-speed:



The S542 Heavy duty 5 speed is a fully synchronized transmission with aluminum case and extension housing. The bell housing is integral to the case. Built in 2 and 4WD versions, this unit is used in Ford F250, F350, F450, and Super duty trucks from 1987-94. The S542 is found behind 300, 302, 351W, 460, and IDI diesel power plants, which means there are three different bolt patterns. Be careful when looking for one for the 460, the diesel pattern is very similar and looks almost the same but the bolt holes don't quite line up (don't ask me how I know...)

If you decide to keep the 391, there are no 5-speeds available to go behind it and AFAIK there are no adapters being made to swap one in. You could pick up a used Gear Vendors O/D unit for probably about the same if not less than that grand you're talking for re-gearing it and get your O/D that way. without having to mess with the rear end. GV O/D units are rated by GVWR of the vehicle so you'd need a heavy duty unit, probably one designed for a motorhome...don't know if they make one that'll handle that 50K LBS though. And you really don't want to use an O/D unit when hauling unless you're on a fairly straight, flat road...

For what you're doing, maybe you want to consider swapping in a diesel. A DT466 might do nicely...

 

go to the trans and diff forum on don the list of forums.there is a thread for brown lipe aux and trans info.mike