Hey fellas,

Id like some input about this before I throw down for a 200-4r. Its going to go on a 69 Delta w/350 and has the O type axle. I plan to upgrade the rear to a posi with 3.90's. I already have the carrier for it. The car primarily sees streets and highways. Ive read up a bit on oldsfaq and the archives here but am not sure the info it has applies to my situation. Any help is greatly appreciated!

Ed

 

You will NEVER find 3:90 gears that will fit a factory 1969 Delta rear-end. Custom housing (Ford 9")yes but big dollars unless you are a fabricator/welder.

 

350 motor...should be a 350 transmission, too. Check that because it'll make a difference.

Column or floor shift?

C.J.

 

There is a way to get 3.90's to fit in my rear. I have beside me a #671 posi that will fit into my O axle with 3.08's bolted to them. Richmond sells gears specifically for this posi unit. They sell the 3.42's, 3.90's, and 4.10's. I should have mentioned this earlier. It is a column shifter and it does have the th-400

Thanks
Ed

 

I dont know if the stuff in oldsfaq also applies to our big bodies.
But it mentions that the crossmember you have for the 400 will work for the 2004r. Is this true? Or will I have to get a custom crossmember?

Ed

 

I've not done the swap, but have been told the 200-4r length is the same as a TH350 so you can use that driveline to get the correct length. I know that 1968-72 Cutlass'es used the same crossmember for the TH350 and TH400's, they just bolt to different locations on the frame side rails. So I would suspect the full sized did the same but am not sure of that. I've got a 1968 Delta Custom that I'm parting out, and it looks like a larger rear end than the Cutlass/442 units. It has a 455/TH400 in it. I also have a 12 bolt posi unit I was told came out of a 1968 Olds 98, casting number 700, so I had thought the full sized of this vintage used a larger 12 bolt rear end. I know of an aftermarket company that makes the shifter detent for the 4 speed automatic for a floor shift. If your going to keep the column shifter I believe you'll have to change the column to a newer one made for the 4 speed automatic. Sounds like a cool project, but just some thoughts to consider. John

 

I talked to the rear end expert over on rop awhile back and he said that if your 69 88 came with a 455, you had the larger C type axle. If you had the small block, it came with the O axle. I don't know if this would apply to 68 but it would explain why your delta has the larger rearend. Im gonna dive into that column shifter comment you made blu, thanks for the suggestion!

Ed