" From: Frank Swygert <farna@xxxxxxx> " " BAD IDEA!! That little four (a 2.5L GM "Iron Duke" in your case) " doesn't have the torque to pull an OD. It probably doesn't have enough " to pull an OD five speed either. The OD gear in most five speeds is " similar to that of the old ODs, so if you do go this route do yourself " a favor and find a T-5. In either case you'll need a lower rear axle " ratio to pull the OD. but... the s10/blazer, which must be similar in weight, paired the iron duke with t5s... " A common misconception is that OD adds a higher gear -- it does just " the opposite. Check the books for any old car with a three speed and " OD and you'll find that it used a much lower rear axle ratio than a " car with a standard three speed. OD reduces rpm in a street/strip car " that's set up to run on the strip without using OD, that's why people " think it's such a great thing! That's not the case in a pretty much " factory stock car though. not always true. standard axle in a late '60s american with 199/t96 was 3.08, but o/d could also be had with 3.08. okay, this is a notch lower than the optional 2.73 without... but even with the 3.08, o/d was set to engage at 38 mph! from my own experience, the 199 is definitely ready by 45. from my limited data, in the late '60s o/d axles were only one notch lower than without. ________________________________________________________________________ Andrew Hay the genius nature internet rambler is to see what all have seen adh@xxxxxxxxxxxxxxxxx and think what none thought _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list