General Info & Caddy 500
Searches can sometimes be problematic but you should try again as all of your questions have been answered many times, even regarding Caddy engines. Lots of very good information is on this board but it is a Turbo Buick board not Chevy or Caddy—maybe YOU revealed too much to “attract” an answer. However, there are others that at least lurk here that have mated the big Caddy to the 2004R. Being one of those I’ll take a shot at answering your question.
To the best of my knowledge all 2004Rs have the BOP multi-fit bell housing pattern—some junk yard claim differently—and will bolt up to any GM product, including the 500 Caddy which is what I have in a 1964 Impala with a 2004R with many PTS parts. However, you will need an aftermarket torque converter with the dual bolt pattern in order to bolt up to the Caddy flexi-plate. I think most aftermarket converters come with the dual pattern.
The top producer of improved-strength parts for the 2004R is PTS, Bruce Toelle’s shop. Give him a call either for prices, advice, or a shop in your area that uses his line of billet parts for the 2004R.
The following 2004Rs are the best ones but are becoming harder to find:
Code Model
BRF 86-87 Grand National Servo casting # = 94 Lipseal servo w/ strongest spring
TAF* 89 Anniversary T/A Servo casting # = 94 Lipseal servo w/ strongest spring
CZF 86-87 Monte Carlo SS Servo casting # = 92 Lipseal servo w/ 2nd strongest spg
OZF/KZF 85-7 442 , 83-4 Hurst Olds Servo casting # = 92 Lipseal servo w/ 2nd strongest spg
Only buy transmissions produced after 1/84; avoid 88 models; 90 models are the best in terms of internal improvements, look also for CT, CU, KD, KJ, KT. The 2004Rs from the later model Caddies are also a good choice for the 500 because they shift smoother and at a lower RPM—good for the torque curve of a 500 and the smoother shift should help the drive train parts and pieces survive longer under the 500’s incredible torque.
The valve bodies/governors in the above models “listed” models are easier to recalibrate for strong shifts, otherwise internals of all 2004Rs are basically identical for each year model. The newer the trannie the more enhancements but the relative strength of driven parts is the same except that the input shaft is improved around ’89 and newer models.
The 7004R is Chevy-only and stock ones break at a lower torque in a manner that often destroys the trannie. The 2004R generally shears the forward drum spine with no major damage--the billet forward drum from PTS (see link below) is around $495 and the shift kit is around $75. Both are the best money can buy. There are a number of other “billet” parts you should also buy from PTS if you do any power enhancements to that Caddy engine. That has been detailed on the board before and I need to go to work.
http://www.2004rperformancecenter.com/
.
