what gears

[hill]

I have a 1970 GTX with an auto trans. The people i get it from were going to make it a 4 speed car, so they changed the rear end to a 4 speed rear(witch is way to low for what i am going to do with the car). My question is what were the stock gears for the auto. I have a beefed 440 with a 727 with a 2200-2800 stall. I was thinking of putting a 3.42 gears with tall 15 in tires. I will be doing mostly street driving.

 

[69HEMICORONETR/TCONV]

I Love 3:23s on the street especially when there behind a stout Big Block. :yes:

 

[Meep-Meep]

I believe you could get anything from 3.23 to 4.10 with any trans. I'll agree with the above post if you do a fair amount of combined freeway/city driving, but if you want something snappier on the low end you can go with 3.55's. Those are still fine on the freeway but long trips can make your head pound if you have louder than stock exhaust.

I'm not aware of a 3.42 gear set for a MoPar. Those are GM numbers

 

[74sundance]

I'm not sure what to use either.Could anyone recommend an ideal gear for street/track use?? I've got an 8 3/4 "489case" with a Richmond gear set Ratio 4.30 Part#69-0060-1 Teeth 43-10 behind a 440 stroked to 500ci with a stage 2 727 trans and 3000 stall.

 

[daredevil]

I like your 4.30 gear sundance. I have a similar combo and i,m thinking 4.10

 

[beezee]

My Super Bee has 440-496 stroked engine,trans ,converter same as Sundance with a 3:91 gear with a tall BFG 295-65-15 Drag T/A, has so far run 11.70 quarter mile,driven to the track and back,distance around 80 miles one way. I,m around 2800-3000 rpm at legal highway cruising speeds. The cam, converter and tire diameter will dictate what the final rear gear ratio should be.

 

[74sundance]

Oh cool,I should add that I have 18" wheels but plan to get a 2nd set of wheels and tires just for the track.

 

[UrbanXX]

If your going to use street tires like 16 or 17 inch I would consider the 3:21/3:23 gear set up. A 3:55 will not give very much more launch off the line if you have a 375 or more HP engine, the 3:55 will just let the tires burn more rubber.
Also with the 3:55 the engine will be turning about 3000 at 70 MPH on the interstate. Remember the 440 redlines at 5500 RPM in stock form.
The 3:55 is a great street gear for the 340 engines but I would stay with 3:21/3:23 on the B and RB engines.