View Single Post
Old 06-07-2012, 08:52 AM   #40
Edahall
Registered User
 
Join Date: May 2011
Location: Goliad, TX
Posts: 672
Re: Increase MPG by 50-80% with a cold vapor fuel system?

Quote:
Originally Posted by 72_GMC_Sierra_Grande View Post
Yeah, looking for a 6 speed manual that will bolt right up to my NP205 and hoping to not have to make any or at least little modifications to anything!!! Maybe what I need is a complete unit trans/transfer case and just swap it all out together!?
The NV5600 is one of the transmissions that will bolt up to an NP205. However, it's still much longer than the SM465 4 speed manual in your truck. That would mean making driveline changes and moving the crossmember back. You'll also need an adapter from someplace like Advanced Adapters to be able to mount it to your engine.

The other option might be to use a 6-speed ZF S6-650 manual out of a 2001 or later Chevy 4x4 truck with the 8.1L. The advantage here is it would bolt right up to your 350. However, GM didn't sell many 8.1's to begin with and finding one with a 6 speed manual is going to be even harder. Most people opted for the Duramax and Allison transmission.

Why are you interested in a 6 speed? Do you do a lot towing? If you do a lot of heavy towing, having that close ratio makes a huge difference. If you're just looking for that extra gear for better cruising, consider another option. Install 3.08 or 2.73 gears and stay with your 4 speed. My 72 Chevy 4x4 4- speed has 3.08 gears and it cruises very nicely at 75 mph.
__________________
1990 ¾ ton 4x4 Chevy Suburban
-Cummins Diesel - 12 valve - factory rebuilt
-6 speed bullet proof manual transmission - NV5600
-Gear Vendors Overdrive - HX35 Holset Turbo
-NP205 iron transfer case
-3.73 gears -2" Lift
Edahall is offline   Reply With Quote