A very late update...............
YES! It is possible. Lots of issues and changes but it's been together for several years now and it's still going great. Changing to this trans along with a change from 2.87 to 3.73 gears and a 3600 stall LU converter has completely changed my car. It is the best improvement I have done to this car in the 29 years I've had it. And there have been lots.
Some of the issues I had and the solutions.......
Too much pump pressure. This was with a .537?? and a .34? boost valve combo. This broke the pressure relief spring causing a loud buzzing in 1st & 2nd over 3000rpm. I re-installed the original spring but also installed a spacer between the spring and the dowel to increase the spring pressure. I use a 7 vane setup with hardened rings.
I ended up with the new style PR valve with the spring Dave supplied with the .500 & .296 boost valves. This combo was a little bit down on pressure so I installed a washer in the PR valve set-up to increase spring pressure. Now it's perfect.
NOTE: There are as far as I know 2 styles of PR valves. The spring seat on these are at different heights so the wrong spring on the wrong valve will result in either low pressure or very high pressure.
It shifted too early so I removed weight from the governor but this had little effect as low speed. I ended up replacing the springs in the 1-2 & 2-3 shift valves with stiffer springs. This worked nicely.
The up-shifts in drive are still too early, about 4500, and this is a KC4 VB so I'm not sure why. I usually manually shift when I'm racing so it's not a big problem for me.
One thing I did have to do after I pinned the governor spring in place was to re-install the plastic spring seat for it as the spring flew out twice. I ended up with the purple spring on the secondary weight (it's about 13 grams) with about 5-7 coils cut off it to retain a similar pressure to what it was without the spring seat. The spring has now remained in place for several years.
I had a pump slide break at the pivot point which caused very low pressure. I managed to limp home without damage so I was lucky. Dave supplied me a 2nd hand slide and all good again.
I originally used the Superior Servo with the wide carbon band but didn't like it so I changed to the Sonnax one. This worked way better but at very light throttle and low speed it clunks loudly when it changes into 3rd. At moderate throttle in quiet.
I dual feed the Directs and changed to the billet direct piston as is recommended along with other changes to correct shift timing as instructed to by Dave. Works great.
I used Raybestos Stage 1 frictions in the Direct & OD packs (with the extra friction in the OD) and the BW in the rest.
All the clearances were set to the tighter side of the range as much as possible.
I went with one of Dave's 9.5" billet LU Converter that Joe supplied him. This is the one with 3200 stall behind a V6 but mine stalls about 3600 behind a 350 chev. I use a home made control box to lock it and got carried away, but it works fantastically! I use 2 vacuum switches, a RPM window switch, a timer and several relays. This will only let it lock if I'm at low throttle (high vacuum), in 4th and above 2000 rpm. Once these conditions are met it starts the timer then locks after 4 seconds. This stops it locking until I'm in a steady throttle/speed state. The second vacuum switch is the low vacuum switch. Once the vacuum is lower than this switch the converter unlocks. This allows light to moderate acceleration with the converter locked with makes for great driving. A bit more throttle, the vacuum drops and the converter unlocks. This stops detonation in my set-up.
So after several year of thrashing this trans I'm more than happy with it. So It is possible to build a TH2004R, at home and make it live BUT, in my case, only with the help and parts supplied by Dave Husek. And after many many phone calls and emails.
Thank You Dave!