Hello all,

I have a 300i6 and a C6 automatic transmission in my 79 F100 Custom. I recently
came across a 79 F150 with a clark 4 speed (3 with od) manual trans. My automatic is getting tired
and I always wanted my truck to be stickshift so
I was thinking of a swap sometime in the future. The 79 has a 302 with SERIOUS damage...I.E. a big hole in a few cylinders....however the trans was freshly rebuilt before the engine exploded. Will the bell housing and flywheel off the 302 work on my I6? What other pointers should I know about a swap such as this? Also, the 79 has a two piece driveshaft....will the shaft from my C6 work or will I have to convert it to the two piece? I measured the two piece and it roughly matches the length of the one I have now...but it must be exact to work so....does anyone know if the lengths would match exactly?

Thanks!

Mike

 

I'm not sure if its the same transmission but my brother-inlaw had an 82 Ford F-150 with the 300-six, 4x4 with an OD manual transmission and it wasn't much count. It failed on him twice, once he was able to have it rebuilt, the second time it ruined the case and it was junk then, He had to buy a used one then, and sold the truck. I talked with other people who had a lot of trouble with this transmission. Its like a car transmission with a high first gear.

 

Mike Dittos on the piece of crap tranny. You can change the auto to manual, but it's a lot of work. It's much easier the other way.
If you must do this but the donor and keep it until you get all the parts changed out and then sell it.

John

 

Yes the bellhousing on the 302 will fit the 300. The clutch/brake pedal assembly from the manual equipped truck will need to be swapped to your truck. If the trans is a column shift you'll need the column from the 79 as well as the linkage. The frame on your auto equipped truck is already drilled to accept the pivot for the clutch push rod. On my 77 with 300 I6 this runs from a socket on the bellhousing to a socket on the left frame rail. The poly pivot bushings should be replaced, but they are still available at any Ford parts counter. If you have a donor truck the conversion is pretty much a bolt-on. On the drive shaft issue, the one piece driveshaft has a slip joint in the transmission tail housing ( at least on my truck ) and the two piece has a yoke on the transmission and a slip joint between the two shafts. I would use the shaft that came with the manual and have it retubed if necessary. Retubing the driveshaft on my 77 cost ~$125.00.

 

Mike:

I'm the original owner of an '81 F-100 with a 300 ci I-6. It originally had that 4-speed trans where 4th was O/D. That trans is junk - don't touch it. Ford only made it for 3-years and they usually lasted 50,000 to 75,000 miles.

I hated that trans, even when it worked. With 2.73:1 rear gears, I was always either lugging or racing the engine to drive at any street legal speeds (35, 45, 55 or 65 MPH). For example, 35 mph was too fast for 2nd gear but too slow for 3rd gear. Also, overdrive (4th gear) was too high and I could only use it on flat ground. As soon as I hit the slightest upgrade I had to down shift to thrid.

In 1992, after babying that trans for 120,000 miles, it finally got stuck in 2nd gear. I went to a wrecking yard and got the 5-speed trans from a '91 F-150. It only had 3,800 miles on it and I paid $850 for it. I had to convert my truck from the mechanical clutch to the hydraulic clutch used in the '91. I love that 5-speed, not only because it's stronger, but because the gears are closer together and that makes the truck much easier to drive around town.

If you can find a 5-speed donor truck you can get everything you need to do the swap. It may cost you a few more bucks, but you'll love the 5-speed much more than that dreaded 4-speed. Remember, when I did my swap the donor truck was brand new (only 3,800 miles before the owner's dad rolled it). A truck of that era will be much cheaper today.

Also, I was able to use my old drive line with the 5-speed trans.

Good Luck.

Bruce

 

The flywheel will NOT work. The 6 cyl. and V8 are not balanced the same.You can get the flywheel that you have balanced to 6 cyl. specs or just buy a V8 flywheel.

 

 

How did you adapt your older truck to the hydraulic linkage on the 90's era bellhousing/tranny? You have an 81, is the clutch and brake pedal assembly like the 70's era with the rod through the floorboard to a z-bar? I have a 76 with a manual brake master cylinder, I have been keeping my eye out for info on swapping a modern manual without ridiculous expense. What is involved in mounting and locating the clutch master cylinder on the firewall?

BBT