I love it when a plan comes together.
The part that's funny about it to me is how this was what I'd figured earlier on, and it ended up being the exact transmission I tried to buy last year. He had stopped trying to sell it but I searched through Facebook messenger (I found it on Facebook marketplace) and messaged him on a whim to see if he had it still after having a couple of disappointing phone calls on the T5. I must have caught him on a good day when either he'd decided the thing had been sitting in his basement long enough or he figured he could use the money.
I'd say I feel as good about the decision as I would on any decision. I know I love driving behind a TKO since I've owned two of them. I love the heavy shifting and the gear whine. So on that part, I'm happy, and I think happier than I'd be with a T-5 of any sort. I also am happy knowing I have a transmission that will hold up to whatever I throw at it. The T-5 is a light duty transmission, no two ways about it. I'm also happy that the transmission portion of the project is done.
The weight gain I'm not too happy about. It is very noticeable. The TKO I can lift by myself but it's one of those "I probably shouldn't for the sake of my back" deals. A T-5 is easy to lift by myself. When I looked up the specs, the difference is about 30 lbs. In the grand scheme that's not too much, but it is noticeable. What's also very noticeable is just how much more resistance the TKO has vs. the T-5. Now part of that is that this T-5 was old and worn and so it didn't have the proper preload anymore, but even a fresh T-5 wouldn't have the same sort of drag that a TKO has. No doubt, the TKO will eat more horsepower than a T-5 would, and it won't be quite as responsive or revvy. But I am putting it behind a 400 HP engine which I do hope to take to track days. Even in a 2400ish lb car, that does seem to be a good idea to have a known good transmission. It will also be something I could put behind a 351 variant if I chose to go that way eventually. Really, I could put it behind anything I felt like putting it behind.
If money were no object, I would probably build up a T-5 with the aftermarket upgraded case, gears, shafts, and tailhousing. That would give me the strength and the light weight that I'm really going for with this car. However, that would easily add $1,000-$1,500 to the build cost vs. what I'm doing, and is from most technical aspects still an arguable worse result. If money were no object I'd also be going for an all aluminum block rather than an overhauled stock block for the engine, and IRS instead of the solid rear axle. If money were no object, there'd be an easy $10k added to the build just in those items, hence why it's not happening.
I'd say one thing that's very satisfying about this is the nostalgia of a TKO. The first transmission I bought was a TKO, back in 2002 when I purchased the 5-speed conversion kit for my 1982 Jaguar XJ-S. That was an original TKO (before they added the TKO 500 and 600 variants). The ratios were different on it, having a 3.27 1st gear and 0.68 overdrive compared to this one having a 2.94 (I think) and an 0.62, respectively. But really, it was essentially the same box. Opening the box, moving the shift lever and spinning the input shaft brought back memories of those years ago when I took delivery of that first transmission. In the end, I only owned that one for 2 years (albeit about 40,000 miles) and then sold it to a friend when I disassembled that car when it had gotten to the point where the rust was obviously at a bad point and the engine was smoking badly. I regretted selling it then. I then purchased another TKO, this time already installed in a '92 XJS, in 2006. That one I kept until 2010, about 3.5 years total. I regretted selling that car.
I think I will keep this TKO a bit longer than the last two. as well as the car it goes in.
Now I have to buy a bellhousing since the TKO uses a different one than the T-5, but the transmission itself is taken care of. I can order those bits, and I already have someone interested in buying up the T-5 in "some assembly required" form.
Next is the rear end. That I have the highest confidence in actually reusing of the major driveline components. This weekend I'll hope to get it disassembled. This transmission also puts me firmly back in the 3.73 gear camp, which is what the rear end has in it now. However I do want to see if I can identify who made those 3.73 gears. If it was a no-name brand, I'll probably replace them with Ford Performance ones.
With the current track record, I'm expecting at this point that I'll be ordering a 331 short block next month after I find out that the block is either no good, or that the machine shop is going to be slow enough that it's just not worth the wait for the cost savings.
Lastly, I dropped the heads off at the cylinder head specialist to get evaluated. I hope they don't find anything significantly wrong with those.