transmission swap or rebuild

[WhtWlf80120]

Got a 81 C20, with an 350 5.7 M engine. Have a standard "H" with granny gear, would like a 5 speed or a possible chance to rebuild the one I have to get more speed. I understand that this transmission setup was the most for that era. But would like to go a little faster than 55mph.

Thanks for all the info in advance.

[Jason S]

The NV4500 5-speed manual transmission from '88-up Chevrolet/GMC trucks is a 'common' manual transmission swap. With the NV4500, you get a fairly low gear plus an overdrive gear. 

Take a look on the forum using the search box for other write ups on transmission swaps; including: 700-R4/4L60E & 4L80E 4-speed autos & 5-speed NV3500 LD manual and NV4500 HD manuals and NV5600 6-speed manual transmissions (and others).

Additionally, you may consider swapping rear axle gears (or complete rear end) for something with a higher ratio.  Really, it all depends upon how you normally use your truck. Example:  If you have 4.56 gears and are normally driving highway, then you may want to go to 3.73 or 3.42 gear ratio and keep your 4-speed.

[WhtWlf80120]

Thanks for the info.

[Engineer]

+1 on the NVG4500.

The gear swap Jason mentioned would be much cheaper.

[Irish_Alley]

or bigger tires. but i have 38's and the sm465 trans you have. even with 4.10 ratio you still would be pushing 2800 rpms at 55 im only pushing 2k at 55. so bigger tires or changing the rear. first thing i would do is verify what ratio you have

[WhtWlf80120]

Thank you for all the reply's. Guess I'll keep it this way for now. $$$ tight. Till I get the other list problems taken care of.