Slick 60's

I have a 65 F100 2x4 with a 390 and COM. Sitting in my garage is a C6 from a 390. What will I have to change to switch transmissions? No real problems with the COM but looking at making the change ahead of problems or the need to rebuild. From those who "have gone before me" what am I in for?

I have not made this change in a truck, but did in my first car a 66 tbird. The car originally had the 428/c6 combo, but the engine was gone and tranny questionable. I had the 390/com setup out of a 65. The linkage was fine. The problems I ran into was that the rear mount on the trannies did not line up, they were about 4" different. On a truck this should not be a problem as you can just move the brace. The other issue was that the C6 had the neutral start switch on the transmission and the com did not. I just jumpered the wires and ignored that one. I do not recall if there were any driveshaft length issues as I had both driveshafts and used whatever fit.

Thanks bruceanderson, that helps. I have the 390 in the truck so it helps to know the cross member will need to move but the linkage should stay the same. I am hoping to be able to drop the COM and slide the C6 right in.......well hoping is the key word. Not much on this truck has gone that smoothly....first time for everything. Any other ideas/suggestions?

You'll need to remove the 2nd crossmember, the one between the 2 mounts for the radius arms, to R&R the C6. Since your truck came with an automatic from the factory, there should be only bolts, not rivets there. The tunnel under the cab is not tall enough for the C6 bellhousing to pass through.

You will need a cooler. The COM came with a funky heat exchanger on the side of the transmission, with lines of coolant running back from the front. They will need to go away, and a newer cooler installed. Of course, I am assuming your truck is mostly original.

Output shaft - The key here is not length of the driveshaft, but where the slip joint in the driveline will be in your conversion.
By the way, you can't have 2 slip joints in the driveline, it is like having too many U-joints in a single shaft, and is unstable. (Ask me how I know this!)

Does the C6 have a bolt-on U-joint as a coupler to the driveshaft? Or does it have a slip joint in the tail shaft?
And, does your driveshaft setup now include a 2-piece driveshaft?
If the C6 has a bolt-on output shaft, you will probably need to shorten or lengthen the current driveshaft that connects to the transmission.
You need a slip joint in the driveline somewhere, and most of our trucks use a slip joint actually in the driveshafts, rather than one at the transmission.
If the C6 is slip-joint, I recommend you change the entire driveshaft setup to a single piece.

I did that swap,like Banjo said there's some drive shaft issues and the shifter arms may not align properly.I was able to get a set from a transmission supply that had a box full of
C6 shifter arms,it was trial and error.They are not all the same.Other than that it was an easy job,well worth it.And also you will not be able to shift into low.Something about the indent on the com column.....go for it!!!!
Dan

I am currently using a tilt column out of a _ _ _ _ _ van. and drive around in "2nd" gear all the time, which freaks some folks out so I am hoping that I can set it up with out much mess. The C6 has a slip joint in the tail shaft and I had thought of just making a new drive shaft to fit....

ras4434 wrote:The C6 has a slip joint in the tail shaft and I had thought of just making a new drive shaft to fit....

Perfect.

If you are wanting the correct steering column, look for one '69 - '72 as well. If you have the '70s power steering gearbox, there are many more in this date range that are the right length. And it will look and work factory.

My truck has had this very conversion done. It was originally a 3 speed column truck that's had a COM column installed to accommodate the 1969 C6 trans. If pics would help, let me know!

The C***y van column is a good one. Most of the aftermarket tilt columns are based on them or are direct copies.

Dan

I have a junk c6 out of a 70 truck that has the correct tailshaft .. to bolt onto the front drive shaft flange.

Ross,

I have done the swap more than once, though it has been years. As mentioned, it is a pretty straight forward process and any issues that crop up are usually easily remedied.
Trans cooler and lines, shift linkage and driveshaft mods are the big issues. Most everything else is nuts and bolts.

Feel free to drop me a PM.

Good luck.

Thanks Roger, I may indeed send a pm when I start. I have a cooler already attached to the COM and wil probably hold off till mid summer. Missed you at the Portland swap meet. How did you do?

ras4434 wrote:Thanks Roger, I may indeed send a pm when I start. I have a cooler already attached to the COM and wil probably hold off till mid summer. Missed you at the Portland swap meet. How did you do?

We were there, same spaces as usual. Hope to be there next year also. Seems after so many years the Portland Swap Meet has become more of a social gathering. and this year was no exception.
I did notice that in the past most people at the swap meet were near my age. This year is seemed that a bunch of old f**ts were stopping by to chat.
I looked for you at Albany last November, but didn't see you. Are you going to take in Rickreall or Brownsville?

Roger, I hope to be in Albany and Brownsville but my wife is in the process of her third back surgery and it is a day to day proposition. Just depends on the day. Thanks for the info on the swap. Hope to start on it towards the end of the summer. I don't know what you mean about old folks...I haven't aged in at least the last 10 years...at least I cant remember if I did.