Just curious here. How will a transmission that was on a 5.0L going to bolt up to a 390 FE? Is there some sort of aftermarket bellhousing adaptor available? Or?
Randy Goodling
CCOA #95
Speed Gems out of Wisconsin makes an adapter plate for the ‘modular’ 6R80 transmission as well as the AOD. Another company Wilcox in California makes an FE to GM Powerglide adapter fyi.
Thanks John. I kind of figured that would be the answer.
Randy Goodling
CCOA #95
check out the link R-code posted. It shows the adaptor plate.
I actually didnt know this swap was becoming a thing, pretty cool actually. Some of the modern ford transmissions have not been popular swaps due to the modules required to run them. Hopefully thats starting to change a bit.
“Coyote Swaps” are all the rage in certain circles. Great aftermarket following which is important. Somewhat common to take a 5.0L our of a F-150 and graft it into a hotrod. My goal of an FE/6R80 has been an interesting study so far.
You have my full support. 
oh yeah forsure thats been happening for years. The transmission swap is what is intriguing.
I’ve been thinking about a 6R80 swap for a while. Curious how well the US Shift controller will be for shift quality. The 6R80 is made by ZF for Ford. I’ve only seen a few for rebuild in the past 10 years, so they are a hardy transmission. I’ve heard of people putting 1000 hp through these, but not sure what mods were done to accommodate that level. With stock components I’d suspect a 400-500 hp engine should not be a problem with the appropriate programming. This sounds like a fun project.
The 6R80 has a great reputation. US shift seems to have a great database of knowledge so as long as you are using a stock 6R80 and OEM transmission fluid it should shift like a normal transmission but can be switched into a race mode as needed. Yes I hear 800hp all day long on stock trans/converter. I have an old friend that works for House of Boost that does a lot of supercharged Coyote engine/trans swaps. High HP with lots of torque and no mishaps. Power By The Hour (PBH) seems to specialize in Coyote swaps and has lots of aftermarket upgrades for the 6R80. No plans for a 6 speed Cougar to run 7’s in the 1/4 mile though. 
I wonder what kind of 1/4 mile improvement a 6R80 would be in comparison to a C-6. Lighter internals and more ratios with smaller drops should make a noticable improvement. The 6R80 is something I might consider for my Colony Park with the 482fe. Even with the 2.80 gear set the rpms were too high on the freeway. Plus, I could run a little more convertor with no worries about being wasteful since the 6R80 has TCC. The wagon ran good with a 3.89 gear. But, no chance of getting on the freeway.
When do you plan on moving forward with this swap?
This is my winter project. C6 is already out and I am sizing things up. Been bench designing for a few months now. I need to confirm one more dimension before I am comfortable purchasing a 6R80, adapter, electronics etc…
I have a 6R80 hanging around. Do you need any measurements?
I’d be very grateful if you could double check this 8-15/16" measurement that I have circled in blue. I’m guessing it should be 4 15/16". Hoping really, since the 68 Cougar has about 5" clearance in that region. I don’t have any 1/4 mile times for the old powertrain but expect a 6 speed to really wake this car up. Generally the 6R80 should be more efficient and gives you the close shift ratios of the more famous manual gearboxes. My 9" rear end has the factory 2.75:1. It’s an open rear end but I will probably drive it with that at first to understand how steep of a traclok etc… I want to consider.
The 6R80 had a 4.10:1 first gear ratio, so you probably don’t need more than a 3.50 rear. The 6R has a .069 OD ratio, very close to an AOD’s .067. With 30%+ OD, you --can-- get away with 2.75 rear, depending on tire size and camshaft. I’d suspect a 3.25 would be the best all around gear. Eh… thinking about it, unlike the AOD, the 6R has TCC and if the programming is good the trans can better cope with a small rear. The AOD had a direct shaft so when it hits 3rd and 4th is it locked solid, which makes it “luggy” with a small gear.
The 6R I have is in a trailer and we’ll need the forklift to get it out. If it’s not raining I should be able to do this in the next day or two.
I’ll be looking forward to what you measure. I am convinced the 6R80 is the best option for me as long as it fits without hacking up the chassis. The AOD can be built to work well and handle abuse but that drives the overall project cost up. Getting a stock 6R80/Converter is fairly easy with plenty of used parts out there. I had an AOD with a 3.27 TracLok back in 1996. Had the poochy 2V 4.6L. Overall I wasn’t impressed with how the transmission worked. It seems some transmission shops are wanting to focus less on AOD.
AOD is usually the simple solution as it requires no electronics. Plus it bolts up to a small block. For about 6 years I ran an AOD behind a 460 in a 70 Cougar. It was a primary daily driver and performed well. Got about 18.6 mpg on the highway. A few mods were done to the trans, the additional in parts certainly cost less than a US shift controller. However, that was in the late 90"s till about 2004. The 6 speed is simply more sophisticated and offers more. Since you have to run an adaptor behind the FE might as well go with the current best offering.
I agree. If I were to fixate on a 6 speed a built C4 with a Gear Vendors overdrive out back would be a very efficient solution. Very high cost however. It will be a big effort for any retrofit. So might as well get the best technology possible. I am partial to an electronic transmission as the vacuum signal on my old 390 isn’t the best. Hoping to get a few more years out of it before a rebuild. I wasn’t so luck with the transmission but limped it around for this season.
Interested to follow along. Been talking about an AOD conversion for my dads mustang, this could be a nice alternative to that.
I have the 6R80 now. Here’s the side by sides with a C6 off my 390 FE. I’ll start a new thread if the project moves forward. Monday I will see how it fits and go from there.
Link to the next stage.
https://cccforum.discoursehosting.net/t/6-speed-automatic-6r80-retrofit-onto-a-fe/13416/1