Hey all,

I have a 66 Elco that was a 6 w/ 3 on the tree. Does anybody know what the read end ratio was? It has a 350 w M21 now and rpm is pretty high at freeway speed.

-R

Anyone?

Could be 3.08, 3.36 or 3.73; you have to check to be exact.

Is the stock rear worth rebuilding? Can anyone point me to some resouce describing which rear ends from other years/makes/models that are stronger will interchange?

66-67 are the same width, some 67s have different spring mounts but can be easily adapted. 68-72 will fit but are slightly wider but will work and also have different spring perches than a 66, easily adaptable.

I've heard some 6 cylinder cars could have a 12 bolt rear if the ratio was 3.73. The normal rear for a standard elky would have a ten bolt which is fine for most use and even some abuse. A 12 bolt is preferred where horsepower/torque is in the 350 or more range but not mandatory.

Here's a link to tons of info
http://www.chevellestuff.com/index.htm

Thanks for the link. That exactly what I'm looking for!