Just got a 200-4R for my 'Vette

[Schmucker]

I've got a '77 Corvette that I'm replacing the TH350 with a 200-4R since it is a direct swap. I thought I had gotten a GN transmission as it was advertised as such and the owner had one torn apart that he was building up and selling parts off of. It was rebuilt once, so I assume the rebuilders took the BR code one and replaced it was a CR code. I got it cheap so it isn't too big of a deal and it works fine. I'm looking at installing a shift kit before I put it in the car. What is a good kit for really barking the tires? Right now I have the anemic emissions 350 with a true dual catless exhaust, but I'm planning on replacing it with a 383 that my father and I will build (he used to drag race professionally) that will put out a good bit more power. The current TH350 is set up to really bark the tires on both shifts (even kicked into a burnout with some slight lateral forces) and I want a similiar feel because it makes the car fun. Also, which ~2500rpm stall converter would be best. I don't want to put an excessively great deal amount of money into it right away. So, no $900 converters no matter how much I'd want one. Since it isn't a GN tranny, it isn't beefed up that extra bit from the factory like I thought it would have been. So what should I do to it so I don't break it? I'm putting a tranny cooler on too, of course. Thanks guys.

 

[gnx7]

you can get a used 12" Lockup GN "D5" convertor with 2400 factory stall for about $50-70 all day long in the parts for sale section.

A rebuild D5 with 2800 restall sells for about $299 with new lockup clutch etc. That will give you some neck snapping results along with a good shift kit.

The transmission vendors here on the forum all have good kits... call them.

-GNX7

 

[GNVAIR]

If it is a CR code....that would have been from a Monte Carlo or Pontiac GP with the LG4 305. Its a low performance unit. All TH2004r's are basically the same. What makes a performance unit (units installed in Turbo Regals, Hurst Olds, 442's, Monte Carlo SS and Turbo Trans Ams) was the valve body and governor.
The Turbo Regal and TTA units also had a larger servo.
The problem you will run into is the WOT shift points will be relatively low. You might want to speak with Bruce Toelle or one of the other trans gurus before sinking any money into it as there are some pretty drastic differences in the valve bodies and governors. You should be aware of this before you start taring into it. This also makes a difference since you said you are planning on putting a 383 in front of it.

 

[Schmucker]

Well, I don't have to put a 383 on, but ideally I would like to. Basically I will have between 400-500ft-lbs regardless of what motor I put in. But that probably won't be until next winter.

I assume it will only take about an evening to install the shift kit, correct?

Who offers the rebuilt D5, GNX7? I want it. The price is right and so is the stall speed. Can you also recommend a shift kit from that supplier? I can beef it up next winter when I swap the motors. Basically I'm sitting at around 200hp/300ft-lbs estimated since I have an open exhaust vs. the stock single with cat exhaust. Right now the TH350 shifts between 6500 and 7000rpm and just barks the tires there. My motor seems to be more than capable to handle those RPMs and not float, so what can I do to the governer to get the WOT shift RPMs up to around that? Just switch to a GN Governer? Man, I was so hoping I would have had a BR transmission so I could avoid all of these problems.