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-   -   200R4 transmission change question (https://www.corvetteforum.com/forums/c3-tech-performance/1756115-200r4-transmission-change-question.html)

dewayne1970 07-12-2007 04:56 PM

200R4 transmission change question
 
This subject may have been discussed in the past, but I am having problems finding the answers I need. I do not want to get my vehicle tore down and not have the parts on hand to complete the change. I have a 200-R4 transmission from an 81 olds. I have a 76 corvette with 350 or 400 transmission. I am not sure if the transmission yet. I want to make the change to the 200R4 transmission. My question is what is needed to make the change possible. Do I need another cross member? If so, what else do I need? Has anyone made the change and how easy or difficult was it? Thanks in advance for the info.

SIXFOOTER 07-12-2007 04:59 PM

All you really need is a different cross member, a different torq converter and a shifter kit to get the shifter detents right, or you can do it yourself. I also prefer an external cooler. Its a pretty easy change
You will need a cable for the tranny shist valve also

mrvette 07-12-2007 05:14 PM

6' I tend to disagree on that cross support, I think if I can get away with my stick shift muncie cross support in my '72 here, by resting the tail of the200 4r on it and having the holes damn near line up...I suspect the automatic versions of same should be able to fit fine....

just use the naked support, no mounting shoe, like I had for the muncie and modded up for the 700 what was in there....

IMO, manually holding 1st gear is a drag racing thing....so to renumber the gear #s on the shifter, and call it quits...cheeeeep.....the current shifter should work fine.....you maybe have to mod the tranny lever the rod/cable goes to, but that's not hard at all...just relocate the centerlines...
KIckdown cables are obvious, to ME anyway....

SIXFOOTER 07-12-2007 06:20 PM

Gene, my TH350 mount holes were about 5 inches away from where they needed to be, thats why I built a new one. But I did it for about $60

marshrat99 07-12-2007 08:12 PM


Originally Posted by SIXFOOTER (Post 1561049455)
Gene, my TH350 mount holes were about 5 inches away from where they needed to be, thats why I built a new one. But I did it for about $60

:iagree: Had the problem with my 79 TH350 to 2004R conversion. Took the BTO route and used their Xmember. For my 79, did'nt need to change the drive shaft. Used BTO's TV cable and other accessories including the shifter plate for an easy install.

mrvette 07-12-2007 08:23 PM


Originally Posted by SIXFOOTER (Post 1561049455)
Gene, my TH350 mount holes were about 5 inches away from where they needed to be, thats why I built a new one. But I did it for about $60

OK, I understand my car was a muncie car...and the cross support was welded in place, and that supposedly the auto cars could have the support moved back or forward to accomodate the tranny....

it would have been about 5" between the Muncie tail mount to the present 200 4r mount sitting directly on the cross support...

I dunno about a 350-400 setup as to where/how....and if there is/was/needed a 'shoe' going forward to suport the tailshaft like my 700 and Muncie needed....I did have to modd the thing to do the 700 tranny...

kinda curious about the stock mounting differances between Muncie and 350/400 trannies...or Saginaw for that matter...

Artsvette73 07-12-2007 10:27 PM

The th350 and muncie used the triangular support to the crossmember. The 400 just bolted to the crossmember.

measurments face of the trans to trans mount
200r4= 27"
400= 26 15/16"

GrandSportC3 07-13-2007 11:21 AM

I don't think that you'll need a different crossmember.. THe 200R4 that I used to have mounted right on my stock crossmember... without any chagnes.. That was an install on a '68!

jerome1979 07-13-2007 12:08 PM


Originally Posted by Artsvette73 (Post 1561052458)
The th350 and muncie used the triangular support to the crossmember. The 400 just bolted to the crossmember.

measurments face of the trans to trans mount
200r4= 27"
400= 26 15/16"


ust a noob question! ok for legth differences between tranny but what about height of tranny mount??
it's important to have a good exit tranny to rear end entry alignement so!?

:flag:

GrandSportC3 07-13-2007 12:18 PM


Originally Posted by jerome1979 (Post 1561058803)
ust a noob question! ok for legth differences between tranny but what about height of tranny mount??
it's important to have a good exit tranny to rear end entry alignement so!?

:flag:

The 200R4 will sit higher but that's not really a problem.. I made 180 drag strip passes (mostly in the 10's) with such setup without any issues.

mdbelanger 07-13-2007 01:02 PM

1977 400 to a 200R4. I got the new cross member the holes do line up with the old one.
http://byfiles.storage.msn.com/y1poZ...fTCGFPe1kxmAXY
http://byfiles.storage.msn.com/y1poZ...IXv9lfWbCBDQkQ

dfolse62 07-13-2007 09:34 PM

Don't the donor 200r4's have a TV cable? How is this different from one that you would buy? Are there any internal changes needed. I am in the same place, trying to get the stuff on hand for my 81. What cars did the 200r4 come in with the universal bell housing. Thanks

I'm sorry. Please explain the wiring for the lock up converter. Where does 12v come from, does it go through the brake switch etc. A diagram of this would help with an explanation of what is "hot" when. Thanks again!!

mdbelanger 07-13-2007 09:45 PM

Check out:
http://www.bowtieoverdrives.com/index.shtml



look under product instructions.

SIXFOOTER 07-13-2007 09:54 PM

My 2004R didn't come with a TVS cable, I had to buy one. There were no internal changes necessary, I connected it up like the diagram says.
Pin A gets 12v anytime the brake is Not applied. Pin D gets a ground from the CCC and applies the solenoid based on speed sensor, coolant temp and vacuume setting. The pressure switch in the tranny provides a path when in 4th gear only

http://i106.photobucket.com/albums/m...TCCDiagram.jpg

dewayne1970 07-14-2007 04:58 AM

This is what I have
 
I have a 76 corvette with 350 transmission and am changing to a 200-R4. Do I need another crossmember? Or will the original one work if I move it back? Thanks for the info.

Artsvette73 07-14-2007 08:00 PM


Originally Posted by dewayne1970 (Post 1561069612)
I have a 76 corvette with 350 transmission and am changing to a 200-R4. Do I need another crossmember? Or will the original one work if I move it back? Thanks for the info.

You can use your crossmember.
You don't have to move it back
Just remove the triangular support bolted to the crossmember you no longer need it. The 200 will now be bolted to the crossmember

1979toy 07-15-2007 08:58 AM

If your car has a T350 in it currently you need a new crossmember or serious modification to yours. If you have a T400 then you can get away with using the stock crossmember. The dimensions from the front of the bellhousing to the transmission mounts are;

T350 = 20 3/8
T400 = 26 15/16
200-4R = 27


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