How far to move axle back?

[martinphoto]

I have a 351w with a 4r70w and a NP205. How far back should I move the rear axle (leaf sprung) to do the NP203/205 low range box? Can it even be done? I know the C6 version can and has been. It appears that the 4R is approx. 2 inches longer. I have both. Will 2 inches be enough or would anyone recommend more or less?

 

[Madgyver]

np203/205 adaptor adds 2.75" i believe. i have a welded version. now available are clocking adaptors.

 

[Broncobowsher]

I always remember the crossmember in front of the gas tank was what limited me from playing with this. Static there is room but when compressed it got really tight. If you have taller bumpstops to limit up travel I believe there is room to go back a little.

 

[martinphoto]

So with the 2.75 inches for the adapter and the 5.75 inches for the 203 reduction box I'm looking at 8.5 inches total in difference vs just the 205. That's a lot and I see why its not very easy to accomplish. May have to just stick to the C6. This is also going to be my daily driver on 37's. Too many damn decisions. :-[ Is the AOD any shorter than the 4R? I don't really want a manual because of neuropathy in my feet.

 

[Broncobowsher]

AOD is 22mm shorter. Not worth it.