I checked first and 6th gear and it seems to have either a .62 6th and a 2.97 1st. Also I've found the codes 1P2111669, 13-86-065-902, and 13-86-066-904. The trans tag is missing and I pulled the transmission from a 1994 z28 that looks like it was originally an automatic.

I believe this a 93 transmission, the better of the two 93 variants. Any kind of confirmation would be great. I've done quite a bit of research but Id like to get another voice on the matter.

Also are there any upgrades that I can perform to strengthen this transmission? If I remember correctly it's rated for 400 ft/lbs.

 

The Borg-Warner format 13-86 codes are in a way, casting numbers and do narrow down what applications it could be. They won't tell you what final machining a part received and don't tell the year, in this case. I'm not sure on the 1P code.

If the case lacks machining for a CAGS port, it's a 93 main case.

If the input shaft length is LT1 length (check relation to the throwout bearing tube) and the 1st gear is about 3:1, you're totally on the right track.

You can ignore "OMG, you got a weak 93 version!"; that's actually a great set of ratios and has plenty of capacity for a 383.

If your car was mine, I'd tear it down and inspect things, check and shim the bearing endplay/pre-load and maybe do 1-4 solid / billet keys and bronze fork pads throughout. Depending on how you value your time / labor, it might be worthwhile to run it a bit before tearing it down so you know what issues it may have. The 5-6 cluster gear fit can loosen up over time.

Are you still running mechanical linkage, or hydraulic?

 

The transmission actually has virtually no miles on it. After a rebuild the owner had other unrelated issues with the car. I checked all the internals out after pulling it this afternoon. From my research I beleive this to be the m29 t56 with the stronger tq rating and the close ratio gearset rather then the weaker m28 variant.

Edit: I'm running hydraulic linkage.