SM420 to NP203 (1 Viewer)

[cpmarcani]

Does anyone know if there is an adapter made to mate a SM420 to a NP203 range box? I have been looking around and don't see anything. I know that it bolts right up to a SM465, but I already have a SM420.

I'm looking to eventually go to a Atlas or Lovell T case.





Thanx

 

[Josie'sLandCruiser]

Hi All:

Well, first off, the SM420 never came from the factory mated to a transfer case; all the 4wd applications it came in had a "divorced" t-case.

Try "Novak" in California: they have lots of custom tranny stuff for Jeeps.

http://www.novak-adapt.com/

Good luck!

Alan

 

[D'Animal]

Just buy a Sm465 and upgrade your stuff.

The Sm420's whine like crazy.

 

[LC_Hamma]

Hi All:

Well, first off, the SM420 never came from the factory mated to a transfer case; all the 4wd applications it came in had a "divorced" t-case.

Try "Novak" in California: they have lots of custom tranny stuff for Jeeps.

http://www.novak-adapt.com/

Good luck!

Alan

GM mated the SM420 to the Rockwell T-221 directly w/ an adaptor (not divorced) in the 60's FYI

 

[cpmarcani]

Other than some obscure Posts on Pirate4x4 it doesen't look like the SM420 is compatible with the NP203. Novak Conversions outright says that on their websight.

If I was going to use a 4sp Atlas I could use the 420 but I am leaning toward the Lovell 357. Which means I will need a doubler, and from what I have found the NP203 is the most durable choice.

Chevy actually used a SM465/NP203 combo in 71-79 Trucks and Blazers, It would be stupid for me not to use the 465 in my application.

The main reason for using a 420 is the 7.05:1 1st gear, realistically there is not that much difference in the 465's 6.55:1 1st. Another argument that could be made it the fact that the 420 uses spur cut gears for 1st and reverse, the 465 uses all helically cut gears, which are inherently stronger.

I guess I answered my own question, thanks for the help anyway.

 

[Josie'sLandCruiser]

Hi All:

Humm . . . . really? That is not what I had heard.

Do you know what the specific application was?

Regards,

Alan

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GM mated the SM420 to the Rockwell T-221 directly w/ an adaptor (not divorced) in the 60's FYI

 

[FL cruiser]

Chevy actually used a SM465/NP203 combo in 71-79 Trucks and Blazers, It would be stupid for me not to use the 465 in my application.

Kinda rare. 1974 only and maybe a couple of 75's

 

[bandy rooster]

might have a better chance finding the sm465/np205 setup...

 

[LC_Hamma]

Hi All:

Humm . . . . really? That is not what I had heard.

Do you know what the specific application was?

Regards,

Alan

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A simple search would've netted a few answers:

- Well I went and purchased another 420!! Number 8!! This one comes with a coupled up ( adapter style) Rockwell T221 transfer case. This set up was stock for a 67 Chevy truck that it came out of

- A buddy of mine has the 420/ 221 case combo. Wanting 250 for all . You interested?

- I have a chance to purchase an SM420 connected to a Rockwell T221 transfer case. Did some searching and found this picture.

- Ok, I just lost the old Rockwell T221 transfer case in my truck and I've never liked the old SM420 four speed (bad syncros and rattling shifter) that's in the truck as well. Here's what I'm facing:

 

[Mark W]

Kinda rare. 1974 only and maybe a couple of 75's

I've heard it said by many that these were the only 465/203 combos out there. But that's not correct. I have found them in blazers, suburbans and pickups all the way to the end of the 203 production. I've got three or four of them here now along with a couple installed in rigs.


Mark...