Need gear ratio advice.

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valiantwagon

valiantwagon

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I'm putting together a street/strip '71 Demon, will be running a slightly warmed over 318 and a 4 speed. Approx. 26" tall drag radials, 8 3/4 posi.
Should I run with 3:55 or 3:91 gears?

Thanks in advance!
 
Valiantwagon, don't overlook the old hot rodder's favorite ratio: 3.73

It's a good compromise between street and strip, and gives very good throttle response. However, 3.73s weren't offered too much, if at all, by the factory so you would probably have to build up your diff specially.
 
Not enough info

1--What are your street tires going to be and how tall are they?

2--What are your expectations for cruise speeds? Mileage?

3--What RPM would you "like to see" and at what speed?

For my present situation, I'm running 28" rear tires and 3.89 (Ford). This is about as low as I'd want to be for 65 mph travel, and even that is "short trips." Over 3K at 65 mph

26" tires is gonna be a lot worse, 3.90 x 26":
 

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Will probably be running a 26" tall tire for both street and strip. Would like to keep shift points pretty low (5200-5400). Looks like 3.55's with a 26" tire would be about 2980 rpm @ 65 mph (about where I would like to be).
 
I have 355 gears and 25 inch tall tires and 60 is a bit uncomfortable as far as I am concerned. I would think that 26 inch tires would help. I am looking at going to 27 inch tires myself just so it will cruise better on the highway and still have some gear left to pay when I want to. JMO
 
valiantwagon said:
Aldo, do you think a 741 case will hold up OK?
Click to expand...

There is a lot of mis-information on the Internet about the 741 Case. I have not seen or heard of one ever breaking from an END User.........Guys start these rumors because the pinion shaft is a lil smaller than the 742 or 489 versions.

I had 1970 Swinger with a 741 case/sure grip and 3.55 gears in a 410 Stroker with a 4spd. I ran that car hard. If it was going to break it should have, believe me!:burnout:
 
Thanks to everyone for the input! I think I will give the 3:55's a shot (it helps that I have a set already)! :)
 
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