231/205 or 203/205 Doubler

TheGriz

TheGriz

Well-Known Member
Joined
Apr 6, 2005
Location
Raleigh, NC
I am trying to make a decision about my doubler setup.
Setup I have:
- SBC 350 Engine
- 4x4 700r4 Trans

I have read that the 4x4 output on the 700r4 is too long to go into the NP203 range box. I have the TH350 adapter, and will try to mock it up this weekend to see if it will fit... if not, I understand that I'll have to purchase a shorter output for the trans.

Option 1 - New shorter output - TH350 Adapter - NP203/F205

Option 2 - Keep trans output - Look for a spacer??? - TH350 Adapter - NP203/F205

Option 3 - Keep trans output - Chevy 231 / Ford 205 (Has anyone seen a 231 doubled with a 205) Can this be done and still allow shifting of the 205? (I don't think the Ford mounting is the symmetrical/circular pattern) Maybe this isn't the best option.

Thanks in advance for any hints/advice.

Steve
 
Im assuming that with your caged rear you have plenty of wb for a doubler, so...

Id go with one of the last 2, because id say that theyd be cheaper then a new shorter shaft...

with either doubler combo id plan to have a mount on the rear case...

the 231 crawl box is designed for the round bolt pattern, and if not possible, id think you could get the right shaft made for it...

let us know how the mock up goes...
 
ai71.photobucket.com_albums_i135_sff5758_YJ_20Buggy_20Build_700r4tonp203.jpg


So sticking with the 203/205 doubler, the output of the 700r4 is ~ 1.5" too long to go into the NP203.

I can't seem to find a premade spacer, but it looks as though one could be machined pretty easily. It wouldn't have to be 1.5" thick, as I could cut down .25-.50" off the shaft quite easily. Unfortunately, it's not splined far enough down the shaft.

It could be a simple flat plate between the TH350 adapter and the NP203 or it could be a 4 bolt spacer between the 700r4 and the TH350 adapter, but with a small flange inside.

Has anyone seen such a spacer or have a good lead in the triangle area to have one machined?
 
id say maybe an inch or so... but you could measure how deep the input of the 203 is, and get a starting point...

id say a spacer between the adapter and case is your best bet..
 
TheGriz said:
I'll need to remeasure the spline length, but I don't think they're long enough. Is there a rule of thumb on how much of the splines should be engaged?
Click to expand...


You could probably take it to a local machine shop and have them cut the splines further back on the shaft for very little $$


The spacer idea would work too, only thing I'd be hesitant about is that the adapter is usually where cracks occur and adding a spacer to it would increase leverage.
 
The TH700 has the same bolt pattern on the back of the transmission as the TH350 and uses a 27 spline output shaft. Since the TH700 only came with the NP208 or later alum t-cases, it's shaft stickout is a little over 2" in factory form. One difference to be aware of is that the TH700 uses 4 metric bolts to secure the adapter to the transmission case.
There are two ways to bolt to the NP203. They are very similar to the TH350 mounting mentioned above.
1: replace the output shaft in the TH700 with an aftermarket output that sticks out of the case by about 7/8". This makes the output identical to the TH350 and you use a TH350 version NP203 with the 27 spline input and a TH350 to NP203 factory 1" thick adapter plate. This is the shortest method. The output shaft cost is $180 and it is available from N.O. Limit Offroad.
[FONT=Arial, Helvetica, sans-serif]2: use the factory TH700 output shaft and the factory TH700 to NP208 adapter housing with a TH350 version NP203. You will have to re-drill and tap holes in the NP203 gearbox to be able to bolt it to the original NP208 adapter housing. You may also have to do minor machine work on the input bearing retainer on the NP203. Call us if you have any other questions. We would love to help. 704-455-1249 Ask for Owen
[/FONT]
 
For under $100 this may be what I need:
http://www.teckpak-fitzall.com/spgm.cfm?id=7Q-35A

I am trying not to tear apart the trans to get a new ouput shaft or have it resplined.

Option no 2 sounds good, but I already have the NP203 range box and sourcing one that specifically came behind a TH350 may not be financially worth while.

I'll look around a bit and see what else is out there.

BTW - I will likely be using two crossmembers to support the whole drivetrain. One under the trans tail and one to support the 203/205.
 
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