14 Bolt swap--Or not

[renegade6]

I have a 72 with stock with TH350 and NP205 4.56 axles (Dana 44 and Eaton H052) front and rear and as a result, not much highway speed. I've been doing research and have come up with the following options:

-Swap to 14 bolt rear with 4.10 or lower ratio and put new R&P in front axle
-Leave current axles and put an overdrive transmission in it when I decide to swap to LS

What do you all recommend?

If I do put a 14 bolt, I want to confirm is that I want the one out of a cab a chassis.

[sweetk30]

no tire size given so i guess 31" for this testing info .

4.56 / 31" tire @ 70mph = 3655 rpm
4.10 / 31" tire @ 70mph = 3287 rpm

overdrive 700r4 swap

4.56 / 31" tire @ 70mph = 2422 rpm

overdrive swap nv4500 stick shift

4.56 / 31" tire @ 70mph = 2595 rpm

play with this http://www.grimmjeeper.com/gears.html

and your best bang for the buck is o/d trans swap . and for you i would prob do a built 700r4 and have it built with the correct length tail shaft for the np205 27 spline t-case you have so no changing parts there . just move the crossmember back and lengthen the front shaft and shorten the rear and swap the shift indicator . also have the trans built for stand alone tcc use .

and since your in texas call this guy up he is good . http://www.phoenixtrans.com/ greg is his name . i have got stuff from him and members on the other forum i am on have even got whole trans from him shipped in to them .

[renegade6]

Excellent, this is what I needed. I have 33" tires. Based on this, I may go with an LS 4L60 or 4L80 swap sooner.

[sweetk30]

your 205 will be harder to adapt to the newer 4l60 ls engine versions as they went BIG 6 bolt pattern on the back over the older 4 bolt style . so hunt for a 4 bolt older version if it was me .

4l80 swap = 32 spline input on the tcase and adapter also .

all this info is no good if you swap to a different t-case . like say a np241 from 90-91 blazer / suburban for the pass side drop and electric speedo guts to tie in to the computer .

the np205 can be made to run a tone ring and sensor for the computer needs offroad design has this service to offer .

both the 700r4/4l60 and 4l80 swaps = longer combo than your th350 is now .

glad this info helped you .

[renegade6]

I've missed this forum. Here, you ask a question, you get an answer without a lot of static unlike some other 4X4 forums.

[sweetk30]

ya i hang our here a bit now and mostly on ck5.com


i stay away from nasty forums with p.i.t.a type people .

and there might be adapters for the newer 4l60 to np205 but i dont play with that combo just 4l80 to 205 stuff my self .

[mongocanfly]

Like k30 says...easiest(cheapest) way to go would be with 700r4od trans...even if you want to swap to LS later on it will bolt right up using adap without affecting drivetrain

[sweetk30]

and i bet after the 700r4 swap is done you will forget the ls swap .

[renegade6]

Originally Posted by sweetk30

and i bet after the 700r4 swap is done you will forget the ls swap .

I did a swap on my son's El Camino. Sure 8s nice just being able to just turn a key.

[Blazerowner]

I have the 4l80 adapted to my np205. You have to make sure the output shaft had the full splines and just cut it to the right length. I bought my adapter from ORD and I’m pretty sure they make and adapter for the newer 60e.

[sweetk30]

i have a factory 4l80-e to round 205 adapter thats super clean i will be listing for sale soon .

i can tell you if your going to do a doubler kit and use a 241 adapter and bolt the 203 box on you need the 4l80-e to have a 4x4 tail shaft . or you will need to cut a hair bit off the 203 input gear .