rpm difference ,between rear gears,373 and 411
 

Does anybody know what the rpm difference is between a 373 and a 411 gear? with a sbc.I guess i should also say ,at cruiseing speed.or 4th gear ,1 to 1.

Go to Richmondgear.com and play with the performance calculators, it will give you exact numbers

in 3rd gear in my turbo 400 (1 to 1 ) with 373 rear gears i was singing along at 3500 rpm's at 60,i would guess that with 411's you would be from 3800 near 4000 rpms at 60 mph..this is why i installed a 4 speed o d trans,,,dropped to 2200 rpm's at 80 mph.i had dodge neons flying past me with the th 400...thats at 60 what happens when you wanna go to 80? i have had this car now up to 145 and it isnt even winding outi would think of installing a 5 speed with the 411 or 373 rear gears cuz your not gonna like it on the highway. plus gas milage will go up.i went from 8 mpg to 17 with the 700r-4 swap

10% difference.

What do you have now?
Neither of these ratios is a highway cruise gear without an overdrive tranny.

:iagree:

To find out the new rpm at a specific speed:
411 / 373 x rpm (old) = rpm (new)

The change will yeild about 10% higher rpms at a given speed.

Our 373 with 1:1 run about 3400@ 65 mph w 225x70-15's I guessing 411 would be about 3800-3900 RPM @ 65mph

I like my 336 automatic much better- must be getting old! about 2900 @65 mph

Correct, which is why when moved to Florida here in '97, the speeds and length of any drive were much higher and longer than anywere near DC region....so in went the overdrive.....at first it was a 700, but I took it out, and put in a 200 4r.....which with 336 feels much better....

Thank you ,:thumbs: