3.54 or 4.10s?

[mbc0724]

Cannot find the tag on my 1971 Charger RT Dana rear end. I know there are other ways to figure out the gear ratio. But maybe someone out there can take a good guess based on their experience and my RPMs and speed going down the road? At 60 mph I'm turning around 2600 rpms. It's a 440 4 speed car. Probably 3.54s? Thanks!

 

[Cranky]

Cannot find the tag on my 1971 Charger RT Dana rear end. I know there are other ways to figure out the gear ratio. But maybe someone out there can take a good guess based on their experience and my RPMs and speed going down the road? At 60 mph I'm turning around 2600 rpms. It's a 440 4 speed car. Probably 3.54s? Thanks!

What is your tire diameter?

 

[QuickBpBp]

Probably 3.54 BUT there is some guess work still as there are some variables... Right speedometer gear? What size tires? Factory Tach accurate?

 

[Fran Blacker]

Is the gear driving speedo right? Agree your gears are probably 3.54's. If they were 4.10's your engine would be screaming and everybody is passing you. Had 4.10's in my car, after 5 miles, had enough of them. Best sales pitch for a 5 or6 speed trans.

 

[Bee1971]

You have the fender tag ? A33 or A34

 

[1 Wild R/T]

3.54's

 

[33 IMP]

My 4.10 gear rr was 3700 at 70mph, with a 28"tire.
I'd bet large you've got a 3.54.

 

[mbc0724]

The tires are radial TAs 60s 15 inch the car is in storage I'll get the exact size tomorrow. Factory tachometer...I think its accurate, but good question. Thanks for all the replies!

 

[1 Wild R/T]

And your tire is about 27.5 tall