Gears

[racerkyle]

I have 1969 Chevy C-10 pickup with a 1994 stepside bed. I take it to car shows, but I also like to have that street/strip kinda truck. It has a 400 small block with holley 650 carb. aluminum intake and a small oversized cam. Flowmaster exhaust. It has 200 R4 transmission. Right now it has 3.08 gears. I want more power but I don't wanna be screaming while I'm running 55 mph. Right now at 55 it runs about 1900 rpm. What would be a little better gear? Thanks!

[Cool Zr2]

that seems high for 3.08, Sounds like 3.73's you running.

[knez]

Cool zr2 sounds right (3.73) what tire size are you running?

[racerkyle]

I checked the tire size, they are 275 60 on 15 inch wheel on the back.

[knez]

I put it in a gearing calculator I came up with 4.10.Thats if I m correct on tire height 29in and a .74 overdrive.You could go 4.56 if you want more out of the hole.

[Frank S]

I put it in a gearing calculator I came up with 4.10.Thats if I m correct on tire height 29in and a .74 overdrive.You could go 4.56 if you want more out of the hole.

 

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Seeing as how he posted he has a transmission with an overdrive gear (200R4) and running that size tire,I'd be inclined to agree.Going 55 mph at 1900 RPM's if the transmission is in overdrive sounds to be lower than 3.73's IMO.

 

Take the inspection cover off,count the number of teeth on the ring gear and the pinion gear,divide the larger number by the smaller number and you'll have you answer.It's not easy to do,getting around in a cramped area and all but you'll be able to get it close and I believe you'll find that you have a greater than 3.73:1 ratio.