Trans ideas

[67 Ol' Bess]

Hello there, I am new here (though I've been a member for a few months, I've just gotten around to posting).

Here is my deal. I just lost 2nd gear in my saginaw 4 speed. Can I fix it? Sure. But I'm using this as an excuse to get what I'm really after.

About the truck: 67 Chevy C20. 8 different shades of blue and primer gray. Mildly worked 350, full exhaust, Holley double pump. It's got the 4 speed turd box that is hooked up to some steep 4:10 gears in the rear.

My dilemma: cruising down the highway (at 55 MPG) my tach reads 3250. I swear to you that I can watch the gas disappear as the needle drops. I get about 7 mpg on a good day. And the gas mileage isn't even really the problem. I'm more worried about the undue stress that is being caused to my motor for long periods of time. Not to mention the glass packs are ridiculous at high rpm's.

My thoughts: bump the gear ratio a bit, to say 3:73. Drop a 5 or 6 speed manual trans to replace the turd that is currently taking up space under the truck.

My next dilemma: I don't know which trans is best for my money. I was told an NV 3500, but they are a bit pricey. I can afford it, but I know I will likely have to get a new drive shaft measured up and made as well. Can I just go with a t5? They are a little cheaper, which would leave some room to do a couple of other things that have to get done. Like paint, for example.

Any thoughts you could share would be beneficial. I haven't even had the truck a year yet, and am not that familiar.