Trans options for my big Chevy

[tscott77]

Okay, forum gurus, I have a question. My 1984 Chevy K30 has a 4-speed(or 3-speed with a granny gear), and 4.56 gears, which means that not only do I get less than great fuel economy, but it also means that the top speed on it is roughly 65mph. Now, I understand that it is a big hauler, and that I might not be able to have my cake and eat it too, but when I get passed on the expressway by some dope in a one ton Ford with a Powder Choke, and he is towing a fifth wheel trailer while doing 80, I get the feeling that there just *might* be something that I can do to extend the top speed in my truck. Any ideas?

[rich weyand]

3.43 gears and 31" tires will get you to 95mph, given that you can do 65 now.

With a "K" that means changing gears in two differentials.  It also means you can't go to an overdrive after the transmission.

Basically, all transmissions are 1:1 in high gear, so you need to change gear ratios.  Bigger tires can get you some of that.

The exception is an overdrive transmission, but I don't know of any stick overdrives.  Someone else might.

[bake74]

     With your big rig I would go with a NV 4500 or something like that, it is made for a big truck transmission.

[Irish_Alley]

 lift ket and bigger tires