i currently have 3:55 gears in my 71 challenger 440 6 pk auto. i am running at 3000 rpm's at 60 mph. that seems a little high to me. i am thing about either getting 3:23? gears or possibly getting larger tires. i am running the stock tire now (235 60 14's)

i was looking at getting some american racing rims, torq thrust d's, to be spacific. but not sure what sizes to get i want to switch to a 15" rim though would also like to have the tire wider in the back?

also what is my max rpm range for a 440

lots of questions i know, but i am quite green to this whole car thing. i bought the car 2 years ago when i was 22 and didn't have much time or money to work on it. now i'd like to get it fixed up so i can actually enjoy it. it surely is an eye catcher!!!

 

well, when i had my 4:88s in my mirada, at 60mph i was around 5000rpm on the highway! i can see if i have some 3:23s laying around..

also, if that is your exact tire size, your tires are only about 25.1 inches tall. my dot slicks are 26, and it is my understand that gear ratio is calculated with a 26" (or so) tall tire, so youre actually a bit steeper than 3:55.

 

For the info you need on changing wheel and tire sizes, go here: http://www.tirerack.com/about/techcenter.html

For the info on your engines max RPM range as well as tons of other info on your car and all other Mopars: http://www.allpar.com/mopar/440.html

Good luck with your upgrades.

 

I've got 275- 60- 15's on my Cuda. mine is a 340 /6pk though. they fit fine and rpms are reasonable.

[IMG]local://upfiles/9974/E0C6ED2559FA4DD3B65D015129E9A348.jpg[/IMG]

 

Now that's the kind of car show I would like, Mopars galore and indoors.

 

I know I'm late to the party but if you're still interested, look into a gear vendor for your car. They attach behind you're current transmission and give you an overdrive. You'll have to have your drive shaft shortened but other than that it's a painless installation. Gear vendors are built very stout so you won't have to worry about breaking it. It won't hurt performance either. In fact, it'll give you a faster top end speed!

Also, switching to 15s and maybe going to a bigger sidewall if they'll fit will help your cruise rpms. You might even have room for a 29" or 30" tire.

 

I like your 'Runner!

 

Thanks! I have seen the overdrive setup your refering to in a Mopar magazine, it gives an overdrive gear for each gear. It basically turns a 3 spd auto into a 6 sod auto and it bolts to the trannys tail shaft.

 

i wonder how much this would cost.

i recently bought some torq thrust d's ( 15"X7) i put 265 60's on the back and 225 60's on the front. i have yet to put them on yet. i'm going to wait till next year to give it a try. the roads are all full of salt around here.

who knows i might be happy with this... well at least i'll look cool!!!!!! that's right all chrome!!!!

 

I remember reading that article. They were saying to shift it correctly to get the most benefit, you would have to go back and forth as you shifted. It is a slick set-up though since it bolts to the tailshaft.