The mounting pad height relative to the output shaft centerline is the same for both. In fact, the 200-4R mounting pad location relative to the bellhousing is just about identical to that of a TH400.

The bigger problem is that the G-bodies use a different crossmember for the 200-4R than for the other transmissions that angles back on the passenger side and bolts to the frame further back than for the other crossmembers. The reason for this is that the mounting pad location on the crossmember wants to be in a straight line between the two ends of the crossmember. If you simply weld an offset into the crossmember, this puts a large torsion load into the crossmember.

The 200-4R was first offered in the G-body in the 1983 model year. The 1983-88 G-body frames have a reinforcement on the passenger side frame rail that allows the 200-4R crossmember to be bolted in place. There is an aftermarket reinforcement sold to allow you to do the same on the 1978-82 frames.

 

No matter what it takes, you will love the 200-4r. Just make sure you get that tranny cross member done right. You could just move that 350 cross member and drill a few more new hole for the frame.. One the nova, I just moved it back and elongated the first set of holes and drilled new back holes. If you go that route, make sure to notch the tang on the cross member so you can reach that one pan bolt that seems to be in the wrong place. That has to be done, so you can remove that pan when you want to. Also make sure you put a drain plug in the pan before you install. Its not so messy when you want to work on the tranny.

 

You could just move that 350 cross member and drill a few more new hole for the frame..

No, you can't. There's nothing to bolt it to.

The G-body frame is different from those of earlier cars. Since these cars all came from the factory with a single catalytic converter, the crossmember, frame, and floorpan are all asymmetric. The 200-4R crossmember is different from the one for all other G-body transmissions. The driver's side of the crossmember bolts to the same holes as for the TH200, right where the frame comes back out to the rocker. The passenger side of the crossmember angles back and bolts to the frame rail under the rocker. As I pointed out above, the 1983-up frames have a reinforcement there. The aftermarket sells a reinforcement for the early G-body frames.

Note in this photo the reinforcement on the side of the frame rail. Also note that you can draw a straight line that picks up the mounting bolts on either end and the trans mount in the middle.

 

DWWL,
We already have the 200-4r from another car - a CK Performance Stage 2. It definitely works pretty well. The governor is set to shift at 5200 rpms at WOT and is beyond rock solid.

Joe,
So the reinforcement goes on the passenger side, correct? Is it welded in or bolted in?

I understand what your describing about the torsionel load created by extending it, but I was intending to add a support to the driver side at approx a 30 degree angle from the mount pad. I was much more concerned about getting the pad height correct.

Let me know what you think.

Thanks for the response - Jim

 

Joe,
So the reinforcement goes on the passenger side, correct? Is it welded in or bolted in?

I understand what your describing about the torsionel load created by extending it, but I was intending to add a support to the driver side at approx a 30 degree angle from the mount pad. I was much more concerned about getting the pad height correct.

Let me know what you think.

Thanks for the response - Jim

The factory reinforcement is welded, but the aftermarket ones are bolt-in. You can get them at the usual sources (Summit, Jegs, etc). Sounds like you understand the torsion issue. If you add an additional support to counteract it, you'll be fine.

 

Got it done. Took some time and test fitting, but lines up well and bolts in directly. I'm going to weld on a mounting pad on the driver side extension to attach a support at approx 30 deg angle to the driver side rail via a 1 foot long piece of 2 x 2 5/16 angle iron that is bolted onto the frame rail.

Thanks for the help.

 

Looks like you may of got it> My picture doesn't show it very well, but make sure your tang on that cross member is notched so you can reach that back tranny pan bolt. got to love those 200-4r trannys.