61 help

[61apachespeed]

hey i have a 61 apache with the 55t rear end. i think i have bigger then 390 gears. i can only do about 55-60 at 3000 rpm down the free way. i found a place called us gears. has any one use them before. cause there about half the price as the other one. i have a 327 and 350t if any one the same set out i would love to know how fast you can go. the few people i have talk to say i should be able to go faster. as any one heard of 455 gears or 495 gears?? thanks

[scotts62]

That would raise your rpm's, you need to get around the 3:42 range if you want to lower your rpm on the hwy.

[Captainfab]

The diameter of your tires will affect your RPM's as well as gear ratio. In my experience the 3.90 gears are the most common in the 55T differentials. That rpm sounds about right for 55-6-mph. In my Suburban I'm running 3.42 gears with 275/60R-15 tires and at 70mph the engine it turning about 3200. Here is one of the online gear/rpm calculators. Thisone is for 4x4's and can be a little confusing. I know you can find others if you search.

http://www.grimmjeeper.com/gears.html

[factorystock]

Patricks Antique Cars sells a 3.38 ring and pinion for 55 thru 62 Chevy 1/2 tons. Standard ratio was 3.90, optional ratio was 4.11 and 3.38.

[61apachespeed]

the other thing it is doing. is it shift hard out of 1st and 2nd is real fast shift maybe 500 rpm does not last long at all. i tryed to adjust it at the vacuum. i did 1 full turn it did nothing. maybe its time to go to the trains shop?