"ur2 slo" is correct, Most 2 speed rear ends will only change your top end speed by 4-5 MPH
if evan that on my 46 I looked in to a 2spd rear end and it only changed my final drive ratio a vary small amount

2 speeds work best for split shifting on a hill with a load


Luke Dahlin

1946 Chevy 2 ton
1966 Chevy 2 ton
1969 Chevy 3/4 ton 4wd
http://www.stovebolt.com/gallery/dahlin_luke_1969.html]1969 Chevy 3/4 ton 4x4