The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Looking For Info on 3-Speed Trans Ratios

C10 - C90 Bill · 01-07-2007, 01:02 AM

Appreciate all the replies.

Just to make it clear, it is a manual trans.

I believe it is not the Heavy Duty type. The truck is a Custom C-10 with a 307 engine and has a synchro first gear.

Why I am asking is, it is a strange set-up. I have what I believe are 3:73 rear gears. When I first got it, I could not go over 60 MPH without it feeling like it was revving too much. I put on 265/75/15 tires on the back and gained about another 5 MPH which made a big difference. But first gear felt too high, even before the tire change. After the tire change, of course, it got a little worse. If I were to guess, it feels like I got a 2.00 or 2:05 first.

Did GM make one with high first gear ratio, like it seems I have?

01-07-2007, 01:02 AM	#5
C10 - C90 Bill Registered User Join Date: Nov 2001 Location: Moneta, VA USA Posts: 3,064	Re: Looking For Info on 3-Speed Trans Ratios Appreciate all the replies. Just to make it clear, it is a manual trans. I believe it is not the Heavy Duty type. The truck is a Custom C-10 with a 307 engine and has a synchro first gear. Why I am asking is, it is a strange set-up. I have what I believe are 3:73 rear gears. When I first got it, I could not go over 60 MPH without it feeling like it was revving too much. I put on 265/75/15 tires on the back and gained about another 5 MPH which made a big difference. But first gear felt too high, even before the tire change. After the tire change, of course, it got a little worse. If I were to guess, it feels like I got a 2.00 or 2:05 first. Did GM make one with high first gear ratio, like it seems I have?