K20 Gear Ratio Question
 

Anybody know the standard gear ratio for a 72 K20 w/ auto transmission? It seems pretty low-geared on the highway, and I'm thinking I may want to swap the gears out for something a little more highway friendly. Any suggestions on a replacement ratio?

Re: K20 Gear Ratio Question
 

4.10

Re: K20 Gear Ratio Question
 

Thanks Tim! That answers my same question regarding my K20 with a 4 spd....:)

Re: K20 Gear Ratio Question
 

Cool, thanks Tim! That's what I was thinking it was supposed to be, but I couldn't find the verification anywhere.

Re: K20 Gear Ratio Question
 

That's the tallest gears you get with that rear.

Re: K20 Gear Ratio Question
 

Unless he has a Dana 60.

Re: K20 Gear Ratio Question
 

A Dana 60 stock on a '72 K20 ?????

Re: K20 Gear Ratio Question
 

Nope, its the round cover GM 10 bolt rear end. I'll probably just get used to them. I have the 70 2wd C10 that I'll probably do the bulk of my highway driving in anyway!

Re: K20 Gear Ratio Question
 

You're right. Then,it would be 4.11. But,that's 1/100th lower :lol:.

Re: K20 Gear Ratio Question
 

I'm a little late here but good chart Tim, thanks for posting.

According to your chart, looks like we cant say becuase he didn't tell us which engine. If the truck had the 350 would be 4.10, otherwise it would be 4.57 with the 307.

GMC K20's got the D60. Nice thing about them is the drums are outside the hubs! And 3.54 tolerance.

Sometimes I think about swapping in a D60 since they accept 3.54's. That could be a good combo with right tire size.