390 into a F-5

[kswillie]

My 48 F-F w/flatbed that has a bad V8 flathead as the orginal motor. I can get (cheep) a early 70"s 1/2 ton with a bad body but it has a nice sounding 390 4v that has a 4-speed (granny gear ). What am I looking at trying to set that motor and 4-speed in the F-5? I know I"ll have to build a front motor mount. Or is there one that will work. What about the drive shaft? The F-5 is still 6v. I"m wanting to use the truck local to haul gravel not as a highway cruser. Thank you for any help.

 

[Jon Hagen]

Sounds like a fun project. Change the old Ford to 12V neg ground(not hard). The engine will fit fairly well, the only tight place is getting the left ex manafold past the steering box and shaft.

You have room to offset the engine a bit to the right to clear things( Chrysler did that in their cars for years).
You will need to rework the driveshaft to fit your new trans.
That pickup trans will not have a rear mounted driveline brake that you need to be legal.
Maybe you can swap it for a light duty truck trans with the brake ?

 

[big fred]

That's always the challenge with those trucks, what to do about the e-brake? Of course, with the vacuum operated 2-spd, it's almost a moot point, since the 2-spd can slip out of gear and leave your truck free to roll even if the e-brake is set...

 

[big fred]

You'll want to put some sides on that flatbed if you're going to haul gravel. ;o)

 

[kswillie]

2x12 sides and a 2x10 tail board for it Fred. Only have a few miles to haul on back roads. The F-5 I have does not have a 2 speed rear end. Would you happen to know what years/model gear boxes had the drive line ebrake that would bolt to the 390? What about early 60's 1-1/2ton? Might be a easy junk yard find. Not that I would want to skirt the law by not having one but for no more than I use the truck I may just have to do without. It's not that I don't like the crash box that it has now. I did learn to haul wheat with one. But I think I'll like the 4 speed that is behind the 390 a little better. Thank's for your help.

 

[Anonymous-0]

Talking about brakes. These F-5's brakes leave a little to be desired. Would just adding a brake booster fix things? My master cylinder is on the frame. If I found a F-6 or F-7 would it have a booster or were they air?

 

[big fred]

My '50 F-6 has a vacuum booster. Uses the same master cylinder as the F-5.

 

[big fred]

I really don't know what tranmission will bolt up. I have the original transmission in my '50 F-6, but the flattie was replaced with a 292 Y-block at some time. Don't know if they bolted the flathead bellhousing up to the Y-block or the Y-block bellhousing to the transmission when they did the swap.