Np231 question

[WinslowS]

I searched and found many differences of opinion, will a Np231 out of an s10 with a 4.3 and 700r4 bolt up to a 700r4 in a full size blazer originally equipped with a np241?

 

[Hogback Fabrication]

I thought the S10 231's are drivers drop

Plus, until the later model years (late 90's IIRC) they used a 5 bolt pattern rather than the six bolt pattern like the 700R4/241.

 

[WinslowS]

I'm looking at using it for a doubler since you can't get a np241 doubler anymore. I don't believe that drivers versus passengers drop matters for the reduction part, only on the second case.

 

[Hogback Fabrication]

I'm looking at using it for a doubler since you can't get a np241 doubler anymore. I don't believe that drivers versus passengers drop matters for the reduction part, only on the second case.

That's sorta correct. The driver/passenger drop does sorta matter, you want the reduction case to be the opposite drop of the second case (or you can run the reduction case upside down).

You probably need a 6 bolt pattern 231 from a late S10. I have no idea how your clocking might work out as far as using a drivers drop case behind an adapter that is used for a passenger drop case; the pattern is the same but its not necessarily in the same orientation. For instance, the Jeep 231 pattern is the same as GM's but its clocked 90 degrees on thier 231's for some reason. You really want to keep the cut off portion of the 231 on the drivers side if your other case is passenger drop.

What I'm getting at is this: If GM used the same orientation for its 6 bolt pattern cases between driver/passenger side, the late model S10 case will work.

If its different (and I kinda think it is), you'll probably have to make your own clocking ring.


I'm making my own 241/205 doubler, and I'll have to run my passenger drop 241 upside down (which requires me to make my own clocking ring). Using a 205 behind a 231/241 doubler also requires shifter clearancing or shifting the case from the rear.

 

[WinslowS]

Thanks, it would be a drivers drop np231 into a passengers drop np 241. I may sound really stupid asking this, but is the bolt pattern between the adapter and the transfer case or the transmission too? Like could you take the 5 bolt adapter off the S10s 700r4 and put it on the 700r4 in a Full size blazer? Or is the 5 versus 6 built into the transmission?

 

[Hogback Fabrication]

I have no idea about the 700R4 stuff but I sorta bet that you can. I thought the 700's tailhousing was removable and interchangeable, but again, that's just what I think. I've never taken apart a 700R4.

Duffy at D.D. Machine will answer all of your questions (I assume that's who you were getting the kit from, AFAIK he's the only one that still makes them).

 

[BGKYK5]

Nothin intelligent to add, but I always though a 4:1 231 followed by a 205 would be the (over)-killer setup. I would say 4:1 231 followed by a 3:1 205, but you gotta draw the line somewhere.

BTW, subscribed for updates...

 

[WinslowS]

Yeah that was the plan, but I'm just throwing the idea around now, not ready to actually commit that far yet. It will probably be a few months minimum.

 

[WinslowS]

Apparently you can remove the tail housing easy.