3.73's are great. Use a mph calculator to see whether you will shift into OD or not from your tire size. That will determine the best gear for you.

On the topic of tranny's not shift into 4th at WOT, that is correct, only the vette/cop car valve bodies have that ability but there is a kit you can buy that will allow you to shift into 4th at WOT.

 

quite honestly, not a clue as how to use the caculator to see if what gears would be best, I do know that my tire size is 245/16/50 if that makes any difference...

 

Ok, using that tire size-3.73s at 5000rpms=102mph, 3.73s at 5500 rpms=113. Using 3.42 gears at 5000rpms=112mph and 5500rpms=123mph. Hope this helps a little.

 

Tks man! according to that, I would guess that 3.43 is the correct gear...right??

 

Well according to what yenko said i would say that the 3.73's would be best. If you were to run at the track you would be crossing the line under 102 which means you would only be around 4500rpm in third gear which is decent. If you had the 3.42's you would be only be around 3500rpm in third crossing the line and leaving performance on the table. With a 305 i would definitely go with the 3.73's, expecially if you do little highway driving and gas mileage wont be that much different.

Another vote for 3.73's

 

Finally someone talking some sense here...

 

ok done!!

3.73 it is!!

Thanks for the info, the debate, and most of all, helping me decide make the right choice!

 

Before you do the switch how about measure your cars performance with the stock gears and repeat the same test with the 3.73 changing nothin else. Measure them both at the drag strip with a full tank of gas.

All that Yenko talk is not relavent to you situation. What is relavent is where your car makes torque. The 3.42 will keep the car in the torque range longer.

Good luck with the 3.73s!! It sure sounds cool.

 

Go 3.42 for auto . You WILL be going into OD if you pic 3.73 There is no reason for you to be shifting at 6000 rwpm in a TPI car. Yout won't be makeing any power above 4500ish rpm so you need a better gearing to keep it in and around that rpm without gongi over( 3.42). Holding it higher than that is just a waste of time and E.T

 

It looks like you've made your choice, and I think you made the right one--3.73, based on your plans for the car... just for fun, basically.

You're not gonna notice much difference in everyday streetability, city or highway, between your two choices, so why not go with the larger? And it'll be nice to have the extra 'fun' that you'll get with the 3.73.

And if you're going to the trouble of swapping gears anyway, then swap in the one you really want. Otherwise, you'll always wonder...

 

Thats what I was thinking,but people have to learn for themselves.

 

you will probably notice when you put it in drive it will jerk into gear a little harder.

 

oh for sure, i know that...it seems like you have to use more force to keep the car stopped while in drive

 

you shouldn't ???? Souns like a torque convertor issue there ???

 

Yea i would definitely agree with D's89IROCZ and that it should not change anything with just the gear change.

 

or it could be the fact ive never driven a V8 automatic car before, never driven a GM car before, or my idle speed seems too high (about 600rpm warmed up). the only other cars ive really driven are a 91 celica, 00 corolla and 03 sebring. and its not like i have to use excessive force, it just makes my foot tired after a long light

 

...and I wasn't talking about sitting still. I meant the transition from park to drive, when barely on the brakes, it jumps a little harder. In thoery it probably shouldn't make a differene. In testing, it did... for me. I went from a stock 2.73 to a 3.73 4th gen rear.