So I am going to put a new set of gears in the Duster, currently has howling 3.23. I do drive this one on the street and a little bit of freeway driving. I also drive it to the track to race.
I am looking for input on running 3.90 vs 4.10 gears.
I am running 28" drag radials
I am leaning for the 4.10 as I believe it will run the quarter
quicker,, what say you??

There is only about 200 rpm difference at 65 mph between the two. (approx. 3200 vs 3000). this assumes no converter slip.
according to the chart on Wallace Racing, there should be approx. a 6% torque increase to the rear wheels with the 4.10 over the 3.90.
Both offer about 25% more than the 3.23.

What cam do you have? You just want to make sure you're not screaming the motor through the lights at the big end.

Wild A$$ Guess - 3.91s

That ratio has worked for countless Mopars. Plus it's nostalgic.

R.

I have always run 3.91s in my street/strip cars. The car is comfortable cruising at 50-55MPH. Personally on my big blocks, I prefer to keep the Rs at or about 3,000 RPMs when cruising for any length of time. Some guys are comfortable with more Rs than that and that might be okay. But at 3,000, my engines have always been okay. A small block might be good with some more RPMs than that, I don't know because I haven't had enough small blocks to know.

The cam is an unknown hyd. little bigger than stock.
At some point in the future I have plans of possibly putting a turbo on this motor, not sure what type of gearing
a turbo would want

Quote=dizuster]What cam do you have? You just want to make sure you're not screaming the motor through the lights at the big end. [/quote]sorry I disagree it better be screaming through the lights it a N/A small block.

I have 4:10's with 29.5" tires. At 55-60 I'm about 2800-3000 rpm.

I ran 4.30's with 29's on the street and 28's at the track that was with a 340, When I put the 416 in the i also got rid of the 29's and used just the 28's with the 4.30. it seem a bit much so I switched to 3.91's and I'm happy with this combo. Runs just as fast and a few less R's on the freeway.

gary