green_79

I currently have a 1979 Vette with a TH350 installed. I was wondering as to whether a 1982 crossmember would fit into my 79? The 700r4 that I'm installing has a K case. If so, does the transmission mount onto the tail housing or the back of the transmission case? Also, do I need to cut transmission yoke reliefs into the tunnel?

oldalaskaman

1.possibly
2.depends on the tail housing and what it came out of
3.never heard of reliefs being needed
4.if its out of a C4 80's corvette, yer gonna have fun

7T1vette

You should not have to cut on anything to get the trans to fit. I installed one into my '71 coupe last year and did not do any modification (of the underbody). The crossmember/trans-mount had to be changed, as did the driveshaft length and the yoke. If you find the correct yoke, it will fit 'as-is'.

oldalaskaman

he wants to use a c3 700r4 crossmember and a c3 700r4 drive shaft, probably work , and I'd know for sure if I could ever have found them at a price that didnt require half my arm, not many around. now I'm glad I didnt find them.

Vette5.5

While not on a C3 Vette, done several 700R4 transplants from TH350's on other cars. Really not much of a deal, having to move the crossmember back a bit and shorten the drive shaft a few inches. The factory TH350 yoke, fit fine.

green_79

I found the 1982 crossmember at "Just Corvettes" in Saint Charles, Missouri. Iy\t is a Corvette salvage yard. He(Danny) had 6 of them. He charged me $100.00. Do not use the 1982 Drive Shaft on a Vette with the iron rear end. The 1982 Drive Shaft is 1" too short. The 1982 Drive Shaft is set up for the 700R4 transmission and the aluminum(Batwing) rear end.

Shark Racer

Isn't a K-case for mounting to a transfer case for a 4x4?

oldalaskaman

they're considered beefier, but with a change of tail shaft housing can be used in different applications
interesting reading
http://www.google.com/url?sa=t&rct=j...rNUJ4aZMp_idOg

green_79

That is what they were originally built for. But, a corvette tail shaft fits up nicely.

Shark Racer

Good to know, thanks to you and oldalaskaman.

oldalaskaman

from what I've read the only real difference is a thicker wall case to help prevent twisting the bellhousing off. I've broke a few 350's that way, real pita

jays78

I have been doing some research on this and it seems that a 200R is a direct bolt on.

Has anyone ever tried this?

oldalaskaman

a bunch, this is only one of many
http://forums.corvetteforum.com/c3-t...ght=2004r+swap
http://forums.corvetteforum.com/c3-g...-comments.html

green_79

I finished the 700R4 conversion. I used the 1982 crossmember. It fit up perfectly in my79. I measure the driveshaft and I measured the distance between the transmission yoke and the rear end pinnion yoke. It measured 26 1/4". I measured from the flat spots on the two yokes, which is essentially the center of the U-joint caps. The difference between the two measurements was 3 1/4". That is with the transmission yoke shoved all the way into the tailhousing. I felt that that would be too much to cut off, so I had it cut to 3". Unfortunately, even that was too short. I should of only cut 2 5/8". The threads that I read pretty much said 3", but I also kept in mind that the manufacturing tolerances back in the 1970's were not as accurate as they are today. No two Vettes are perfectly the same. So I measured it three times and still got it wrong.
The transmission yoke contacted the passenger side of the tunnel by 2mm. I disconnected the driveshaft from the pinnion yoke and slid it forward that missing 3/4". It cleared but was still too close for my taste. It has about 3mm of clearance, enough to slide a credit card in but no more. I was not about to spend another $200.00 to have Driveshafts Unlimited build me a new driveshaft that would be 3/4" longer, and still only have 3mm of clearance. It broke my heart to do this, but I grabbed my trusty 32 oz. ball peen hammer and dimpled the tunnel in a small are to create a 1/2" yoke relief. I can now at least get my little finger between the two now. This way, if I break a motor mount, there should be plenty of room for it to go. and the you doesn't come through the floor.

green_79

With all that said, there still was the issue with the parking break cable. As it is with the drive shaft at the current length, there is only 2mm of clearance between the cable and the driveshaft yoke. If the drive shaft were 3/4" longer it would still only clear by 5mm. I chose to make an adapter for the current parking break wheel to move the wheel back 1". That will give an easy 3/4" of clearance.
Photos to come.

vette400

I installed a 200 4R in my 79 and it was a direct bolt in. I needed nothing changed. Some guys said that they have problems getting around the exhuaust but with my side pipes not an issue. Can use the 79 crossmember and yoke and original drive shaft. Then you just have to wire up the lock up and your done. Probably the easiest up grade I have done to my car. Plus is was nice dropping a 1000 rpms off my engine.

green_79

As you can see I have only about 3/4" of clearance.

green_79

As you can see there is only about 2mm of clearance for the parking brake cable. The top cable lead is the issue and not the bottom. It is an optical illusion in this photo. I need to move the wheel back some.