Saginaw 4spd 200-4r swap

[Angel Valles]

I have heard that the th350 short nose is the same size as a manual 4spd and that the th350 can be directly replaced by the 200-4r.

Does that mean the 200-4r can replace the saginaw 4spd in my '53 chevy?

I don't mind resizing the drive shaft if i can use a bolt-on yoke on the 200-4r.

Any advice?

[tmoble]

TH350 and th200R4 are the same length. tranny cooler lines can be tweaked to work. Shifter will work but Low will be a little hard to get. tranny mount and crossmember work but the crossmember will slide back to where the TH400 would be. Driveshaft works. Dipstick tube works. TV cable that looks like a kickdown cable is critically important. You can get an adapter gizmos to bolt on the linkage of most carbs, use a TH350 cable bracket.

Does your trk have a modern engine? some kind of small block? Sorry, no bolt on yoke that I know of.

[Angel Valles]

Yes this engine has the modified head where the head, intake and exhaust are all one piece. The starter is bolted to the block. So i am sure it will bolt in easily. The previous owner even put in gas pedal bracket for an auto-trans. So I am all set except for get the rear hooked up.

Do you think the threads talking about the length include my early saginaw? Becuase they are mentioning vegas, camaros and c10s.

Either way I won't hesitate to shorten the drive shaft.

I read one thread that mentioned a bolt on yoke on an older 200r4 casing. I had a Powerglide once and remember seeing the output shaft having threads in the center. So I am really hoping the 200-r4, even an old one has that feature.

If I could find a '55-'64 3rd member i would go that route too but only after knowing for sure the bolt-on yoke isn't possible on the 200-r4.

Thanks for your answers!

[mr48chev]

If you are running a 250 with a car four speed it should be a pretty direct swap.

I am assuming that you have a later 250 six with the integrated head.

[Angel Valles]

Well i am not sure what it is, lol. I have asking for parts for it as a '72 engine out of a c10. I say itsd a 235 and I don't get any questions about it so i keep doing it.

But i am comfortable with the 2004r bolting on to it and relocating the cross memeber.

My next hurdle in my plan is the drive-line.

I hope to bolt a yoke to the transmission to use the existing drive shaft if at all possible. You know the torque tube is reverse making the slip yoke rest in the rear end and the u-joint lives on the tranny.

As long as the seals are good I should be able to leave the torque tube open. Leaving the drive-shaft itself to be shortened and balanced if anything.

Anyone agree or dis-agree?

What do think mr48chev?

[tmoble]

I don't think you're going to find any bolt on yoke deal for a 200R4.

I'd look at modernizing the rear axle/driveshaft deal. If you want to actually drive your truck much.

[Angel Valles]

Yeah me neither, i guess he was talking about a th200. I'll try to locate a '55-'64 pumpkin.

Any ideas on preventing the axle to pivot once the torque tube is gone?

[sweet70beast]

I believe that you will have to replace the whole axle because the old one is meant to pivot. The only auto trans that I can think of that came with a bolt on yoke is the TH400(475). Which usually came in the 1 ton and bigger plus in motor homes too.
If you're still using the torque tube I am figuring that you are using the original truck 4 speed, right? That is shorter than a 2004r. If it is the 60's and 70's 4 speed car saginaw than it should be the same length.
If your motor came from a 72 C10 and is a 6 cylinder it could either be a 250 or a 292.