It's been roughly three years since Heard and I put this article up here on the 'Barn, and although we have probably received about twenty or so PMs with questions about our Jeep T5 conversion, we haven't heard of anyone completing one of these conversions...until now. I've wondered if it's possible that the few SERIOUS candidates for this conversion might just need a little more persuasion in the form of a testimonial about a running and completed car with well over 3,000 trouble-free miles on it. It just so happens that another candidate PM'd me last week asking a question, and in answering him I came across a T5-related link on the HAMB that I was not familiar with. In that nine-page link, I came across a '32 coupe that Cory Taulbert owns. Many of you know Cory from these pages here on the 'Barn. Cory always has "killer" cars, and the guy only has one way of doing things..."FIRST CLASS"! Turns out that Cory has put this same Jeep T5 with 2.95 1st gear and 0.63 O/D behind his SBC, and bolted-up to his shortened torque tube. Forget that he's using a SBC...it just as easily could be a flathead, as he is using the same flathead adapter that Heard used on his flathead-powered '35. So, to make it easy for y'all to follow, I'm gonna cut n' paste Cory's lengthy post (with pics) from the HAMB article. This combo just has so many benefits for someone that seriously wants to DRIVE his old Ford, and it works! See Cory's article below! DD
__________________________________________________ __________
__________________________________________________ __________
By: Cory Taulbert
Last year, we put around 6,000 miles on the 5w after the refresh. The car functioned perfectly fine but every time I drove the roadster (with a T5), I couldn't get over how well that trans performed compared to an early Ford trans. Since the car was done (to some extent), I did not want to have to redesign a rear suspension to go open drive T5. Knowing my two constraints, it meant I was going down the path of a closed driveline T5 conversion.
The closed driveline T5 leaves you with two options - the S10 4x4 trans, or the Jeep 4x4 trans. Both variants are non World Class units (more on that later). Even though the S10 variants are more plentiful, I preferred the more compact rear housing of the Jeep variant. I ordered a closed driveline kit from
@Kato Kings here on the HAMB, and purchased a rear housing and S10 NWC box off of ebay for mockup.
I also decided that I wanted to retain my stock mechanical clutch linkage (it worked very well), so I decided to put a Flathead to GM trans adapter behind the sbc to early Ford adapter I already had. This had two advantages - 1) it allowed me to retain the original clutch system and 2) this setup was less bulbous than a GM bellhousing, meaning less floor intrusion. I picked up an adapter kit from
@krylon32 here on the HAMB that he sells for putting a T5 behind a flathead.
With my mockup pieces together, it was time to get to work. I got the floor out, followed by the engine and trans. I pulled the torque tube and driveshaft out, leaving the chassis open.
With a lot of measuring, I determined that the top "bridge" of the k-member obviously had to go. The center hole, which allowed the driveline to pass through originally, also had to be enlarged. I rough trimmed this opening first to get the transmission through. With the carefully piloting of this transmission through the k-member, I was able to leave the "belly" of the structure untouched. This was very important for me as I did not want to disturb the wishbone attachment.
Next, I needed to build a rear transmission mount. The
@Kato Kings kit allows you to use any early Ford rear trans mount. I chose to go with the '37-41 rear mount, as I thought it would work best for my application. Now this car already had a set of Industrial Chassis k-member legs, which worked very well for this conversion. I think that these legs more than offset any torsional stiffness that I lost with the removal of the "bridge" of the k-member, but it also provided a solid structure for building a rear trans mount.
I built a curved boxed structure that attaches to the bottom flange of the k-member legs, and also attaches to the vertical walls. I felt this helped create a torque box (paired with the k-member), further offsetting anything I lost with the removal of the "bridge".
Since the trans was now firmly located, I was able to mark the k-member for a final trim to allow sufficient clearance for any engine and trans movement. Once that was complete, I welded a return flange to the k-member off the rear that wraps from the top flange, all the way down, around the trans. This was another measure to ensure sufficient torsional stiffness.
Even though the "heavy" fabrication was done, I still had a bunch of small, but important, things to build.
There is no longer a short throw shifter available for a Jeep T5 shifter. I'm a big fan of Pro5.0 shifters, so I picked one up for a Mustang, and machined the base plate off of it. I then drew a new flange in CAD, and had it laser cut from aluminum. I welded the two pieces together, finishing off that task.
Next up was tackling the torque tube and driveshaft. In the middle of this T5 project, I decided that I wanted to build a fixture for shortening torque tubes. I've always been hesitant of the angle iron method (I know it has worked for a lot of people) because I was very concerned about ensuring both ends very not only parallel, but also concentric. If you look at a cross section of an original torque tube, you can see that the tube is not perfectly concentric.
I picked up a machined steel mandrel, and built a fixture that registered in the front bearing bore of the torque tube. The other end utilizes a sliding collar, with a flange for the banjo end to bolt to. I've found this fixture to work very well.
I then moved onto the driveshaft. This car had a '33-34 shaft in it from before. I decided to shelf it for a future project since it was already the correct length for a '40 rear end in a '32 frame. I had some extra front couplers from '35-36 driveshafts that I had built exhaust systems from. I machined a pilot in the back end to allow a press fit into a new chromoly DOM tube. I then picked up a 6-10 spline coupler from
@Mac VP to use on the rear. This coupler works out well for a guy building a tube driveshaft with 6 splines as the coupler has enough diameter on it to be turned down to fit in shaft. Just like with the front coupler, I turned a pilot on the 10 spline side to allow a press fit into the tube.
I used the tailstock on my lathe to press the couplers in each end of the tube. After that, I checked it for runout before welding everything together.
Since the T5 is a bit taller than the early Ford trans, I did have to slightly trim the toeboard and floor for clearance. I made a trans tunnel from some 18g steel to cover this transition. It looks taller in the photo, but the peak of the tunnel is about 1.5" from the floor.
As I had mentioned, both the S10 and Jeep transmission were only on the non World Class design. The Jeep trans in general has a pretty poor gear ratio selection, so I knew that I needed to change it. I wanted to utilize the 2.95 gear set used in many Mustangs and Camaros, which is a close ratio gear set that's very fun on the street. I also knew that I wanted a World Class box for the improved syncros and higher torque capability. That set me off in a big research project to understand how I could get there. It's a big story in itself, but the important take-away is that you can't swap mainshafts between NWC and WC. I obviously needed the very short Jeep mainshaft to use the Jeep rear housing. To make a long story short, I was able to locate a factory Tremec shaft that had the Jeep length, but the WC interface.
Once I had that in my hands, I sent my mockup parts and mainshaft down to Astro Performance in Florida to assemble the trans. They've done a few open T5s for me, and I've been very pleased with the work. They put together a 2.95 gear set using all Tremec made parts, and a good used 2.95 input since Tremec no longer manufactures one. It's paired with a 0.63 OD. Once that came back, I ran a dial indicator on by bellhousing combination to confirm it was in tolerance before bolting up a new RAM diaphragm clutch. Once the trans was in the car, I assembled the rear mount and got the engine/trans secured in place.
I've had the car back on the road for a couple of weeks now, putting more shakedown miles on it since the T5 conversion. I've logged about 250 miles so far, and the car has been working out very well.
I should also mention that while I had things apart, I sent the rear end to Hot Rod Works for a refresh. We ended up replacing just about everything due to some past work that wasn't up to par - this rear end had been converted to slide-in axles at some point in its life using early F1 parts.
Guess this thread is as good of a place than anywhere to drop in the update that we drove this car to the Hot Rod Hill Climb last month...(OCT 2017). The car ran well there and back, and we even made a couple of runs up the hill too!
((I'm seeing about 74 mph @ about 2,500 rpm...DD))
The total trip came in at 3,061 miles....(OCTOBER 2017).