5 spead swap on a 350

[jggriffith1776]

I have a 84 GMC k2500 5.7 350 with a granny low 4 speed and some things have come up with my f150 that I have to use my GMC as my daily, I am all for smiles per gallon but with gas prices I'm thinking about tans swapping it with a nv4500 5 speed. Has anyone that did this swap figured out their mpg after? I am open to other transmissions but I'm on somewhat of a budget and I do quite a bit of towing so I'd prefer a HD trans. Thank you for your input.

 

[Shorty81]

Welcome from Ohio. I don't think you are going to improve enough mileage to justify the cost and time to change tranny. Maybe go with a taller tire? That good ole SM465 tranny is as good as they come.

 

[jggriffith1776]

@Shorty81 Ok thanks, Would a 2 or 3 speed gear splitter on the 465 effect mpg enough to look for one? And I planned on going to 32's at some point.

 

[Shorty81]

I have no experience with gear splitters. I have a K20 with 496 BB. SM465, 208/3:73, 32" tires and I get 11 mpg no matter what I do or tow. I'm also light footed and drive the old girl gently.