Rear Gears

[plumcrazzy]

Background Info: '70 Challenger, 440 six-pack, 4-speed, stone stock driveline with 3:54 rear. Car runs very well but I think I would like to change the rear gears for just a little quicker launch--maybe 3:73's. Just looking for opinions on what gear ratio, manufacturers, ideas, anything. Rear is a Dana 60 BTW. Am I correct in the assumption that this should not be a difficult swap. Any ideas or tips on the swap would be appreciated. Thanks in advance. 

[Rich G]

Don't think you'll see a whole lot of difference going to 3:73 from 3:54. Might want to go to 4:10 for the trouble. It's not rocket science but you will have to set pinion depth and backlash , not just a bolt in.

[73sixpack]

You won't even notice that little of a gear ratio change, you'd need to jump to 3.9 to 4.1 range to see much difference. A lot more torque in each gear and a lot more RPM to go along with it. I use 4.10's in mine when drag racing with 29" tall slicks, but when I'm not racing it I put the 3.23's in. It's got an automatic and even with the 3.23's 1st gear is all but useless, even 40 mph rollons boil the tires to the point of smoke unless you let off. If a guy runs drag radials or something comparable (I have some Hoosiers DOT drag tires that hold it) you'll have better luck, keep in mind drag tires do not corner well at all. Do some calculations for the tire heights you have or are going to get along with the RPMs your willing to put up with.

[WAMA72Challenger]

73sixpack I have 3.23 in the rear and due to the ongoing restoration I haven't actually been able to drive the car I was thinking of the idea of upping the gear ratio but are you saying even with the 3.23s it'll roast the back tires at 40mph

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[73sixpack]

Mine will, it does have a 484-284 MP hyd cam, 2.14 intake and 1.81 exhaust, pocket ported 906 heads, headers, 11" TCI converter, recalibrated the tranny governor to shift at 6500. (and tuned well, when we first took it to the track the first pass was only 13 and change) It has run a best of 11.8 @ 115mph.

[brads70]

I'll be soon swapping out the 3:54 (Dana S60) to 4:10 I bought the rear end from Cass as well as the new 4:10 gear set/install kit. Cass highly recommended using Dana gears( which I did) over aftermarket, just thought I'd mention that.

[dodj]

I'll be soon swapping out the 3:54 (Dana S60) to 4:10 I bought the rear end from Cass as well as the new 4:10 gear set/install kit. Cass highly recommended using Dana gears( which I did) over aftermarket, just thought I'd mention that.

Changing to 4.10 because of the 5 speed ratios and 3.54's don't work well with the stroker?

[4Cruizn]

I have a 4:10 Dana gear laying around and would part with it . . . 

[brads70]

Changing to 4.10 because of the 5 speed ratios and 3.54's don't work well with the stroker?

Yes with the OD / 3:55 at hwy speeds rpm's are to low for my engine combo