: For those interested in swapping older "real" engines in front of newer transmissions

The Ape Man
09-21-07, 12:03 PM
Here's a link to some really good info. The stuff about the 2004R would be a lot of use to people here who have given up on the HT-4100 or want to lose their 307.


09-21-07, 10:57 PM
Excellent find thanks. This is a gem of information.

TH2004R to TH350/400/7004R?! ZUUUUH?! *bookmark*

09-22-07, 02:18 PM
The Olds FAQ is probably the precursor to the Wiki! I was on the list when all that was being done, basically one of the guys kept taking all the info and compliling it off the emails that were going back and forth. It is a wonderful wealth of info.

The Ape Man
09-22-07, 04:57 PM
Where was the %##$^ internet when I was hooking a 507 up to MY 2004R? Al $###$Gore hadn't perfected it yet. Never got that thing to shift for 2 cents but it did last a while. The Grand National people were getting excellent service from those same transmissions.

09-23-07, 12:10 AM
Ape Man; how well did it work? How mild/wild was your build? Any modifications to the tranny? Curious on any info ya got - good, bad, ugly.

The Ape Man
09-23-07, 09:52 AM
Actually, the whole blurb is on this board a while back.

I used to spend a lot of time doing crazy stuff with Cadillacs.

This was done in 1992 so a few things have changes as far as parts availability. It's easier now.

The engine was a .030 over 1975 500. No mods other than the overbore. I like low end torque and gas mileage. I only do mods that will improve power AND mileage.

I purchased this beautiful 1983 Coupe Deville with low original miles on it's second blown apart (according to the owner) HT-4100. The HT-4100 was OK but it sounded like the bottom end was ready to fall out. The installer didn't know how to deal with the TORX crankshaft flange to flywheel bolts.

Anyway, I sent the transmission out to my trans guy and he put in a newer model year front pump, hardened sunshell and some bearings where there were factory bushings. He supplied an adjustable detent cable. I modified my carbanator with a baseplate from one of these compuker feedback Olds 307 powered vacuum line wonder Cadillacs.
The baseplate allowed the correct geometry for the detent cable but you have to drill 2 holes for the idle mixture. These baseplates also allow for a richer idle mixture than the Cadillac carbs. I made a bracket out of a factory detent bracket and brought the cable around a pulley with a bearing mounted on the intake to the carbonator linkage. Looked like it was designed by Wyle E. Coyote. No birdseed was used though. The 500 flexplate (flywheel) needed to be drilled for the 2004R converter. The new holes land up right where the flywheel's stamped plate takes a step. I filled in the step with a fender washer on each bolt. The washers were ground down to a half moon shape and matched for weight. You can buy a bolt-in flywheel these days. Starter was a regular Cadillac case starter with 8 volt windings.

I built my own lockup controller from a early 80's S-10 Blazer normally open vacuum switch. I hooked a relay to interrupt power with brake lamp voltage. Another relay went to the 4th gear pressure switch in the transmission. IIRC I couldn't hook this without the relay because it was normally closed. There was a reason. Anyway you can buy all this crap at a speed shop these days. I had an adjustable vacuum chamber made from hoses and an old Ford (sorry for cursing) OSAC valve which slows vacuum buildup down. This delayed the lockup for an adjustable amount of time.

Cruising gas mileage was not any better than the same type car with a 2.21 rear axle and a TH-400. I had the factory 3.41 or 3.42 axle ratio so the overdrive was close to the ratio you would get with an older 425 powered RWD car. The car had a lot of gear from a standstill but it was useless as the open axle allowed the tire to go up in smoke. You need a posi with this chassis with any power! The 2004R would not shift properly under full power either. The link I posted pretty much gives all the reasons for my shifting problems. I could have made the car get much better highway economy by sticking in a 2.73 axle but I went back to a TH-400 for simplicity and better shifts.

My '83 CDV was murdered about a year later by an inexperienced driver who made a stupid mistake. My wife was driving the car and had a choice of hitting a pole, oncoming traffic or the idiot kid. She went for the kid. She had been going 45-50 MPH and broadsided the other car. She walked away without a scratch. When I got there she was following the other driver in circles around what was left of his car (it was the size of a couch and the kid was limping pretty badly). The cops asked me to please call her off. Mr Allstate gave us 25% over book value for the car and let me keep it.

I fitted the same stuff into out 1982 TransAm later that year. Tried the TH-200 again. I rewired the whole entire thing for Cadillac EFI injection. That car got 24 MPG on the highway. I never once cracked it fully open from a standstill for fear of breaking the little factory ring gear. Plan was to change that. I landed up using the car for work and it was a pain keeping a car that was an experiment going 600 miles a week....Before it was over I went to a TH-400 there too. Gas mileage went down to 12........