tranny swap for 390

Clutch, transmission, rear axle

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R.Smith
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tranny swap for 390

Post by R.Smith »

I've decided to toss the column shift on my 68 F100 and I'm looking for a floor shift gear box that will bolt up to a 390. A friend has offered a 4 sp out of a 67 mustang that had a 289 or 302. Will this bolt up?

If not, what would be the easiest swap. I'm not looking for anything hot rod, just something reliable.
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390Nut
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re: tranny swap for 390

Post by 390Nut »

Assuming you have a 3 speed manual from the sounds of it, here's my :2cents: It might bolt up to your bellhousing, but the input shaft will not be the correct size. Also, those car trannies can handle plenty of torque, for the most part, but they weren't made to handle the stress of all that weight. Trucks are a lot heavier than the early model Mustangs, and you'ld likely be replacing that tranny after too long, especially if you actually use your truck, and not just drive it.

Two easy ways you can go about it. One, get a floor shifter for the tranny you already have. B&M, Hurst, etc, make floor mounted shifters for the Ford 3.03 tranny (3 on the tree). They aren't that expensive, nor difficult to install. This option is pretty straight forward, if you dont have a removable panel on the floor, you'll have to cut a whole and fabricate a cover (or get one out of a junkyard from another floor-shift truck).

The other easy option is to go with a 4 speed, either the T18 or NP435, both of which are very common in these trucks. They really are 4 speed trannies, but you'll not use 1st gear much. It's made for getting you moving with a heavy load, but thats about it, so you'll actually start out in 2nd for normal driving. This option means simply swapping the trannies, and most likely the front half of the driveshaft, and possibly the speedo cable.

There are other options for manual tranny swaps, but they gain complexity. 5 speeds are one swap that people do, theres lots of threads on this topic already posted (and I dont know much about the swap myself, so I can't speak much of it. :wink: )

If you are swapping from an automatic, there's a lot more involved. You'll need the clutch/brake setup, bellhousing with throwout fork, the equalizer bar (Z-bar) and all linkage, as well as a flywheel for the clutch assembly. You'll also likely need the front half driveshaft and speedo cable.
Paul
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`69 F100 390 4spd driver
http://www.fordification.com/galleries/ ... ?cat=10251
Dura-Spark II Conversion info at:
http://home.comcast.net/~390nut/Dura-SparkII.htm

Pipes71 did once say, "bumps and bikes.. what a great combo!" :thup:
fmartin_gila1
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re: tranny swap for 390

Post by fmartin_gila1 »

Ensure that the 4 spd your friend has is not the Dagenheim. It was not a good tranny for a car, much less a pickup.
Fred
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