4.10's or 4.30's for N/A? NEED ADVICE PLEASE!

[axeman]

i seriously want to get into the 12's with my stock heads and cam. i have 3.73's right now, but they are just not going to cut it. if i go with 4.10's i'll cross the line ~5350 rpm with my 26x11.5" et streets. if i go with 4.30's i would cross the line ~5600 rpm with the same tires. since i need new tires anyway, i was thinking about getting a 27" tire and getting the 4.30's. i would then cross the line ~5450 rpm. what do you think?

 

[StangFireman]

Hmmmm, how about some 4.56's? LOL How's it going? I sold my car and bought Bob Cosby's old FS car. E7 head, stock cam and a few tricks. But it has 4.56's and a 275/60 DR. Most guys that run FS use a 4.30 with the GT40 heads and they say for the E7's to run a 4.10 but why would I want to change gears? LOL Bob said he was crossing the line over 6K rpm. I figured it up to around 6200. But he ran a 12.18@111. I think after some suspension work I'll be in the 11's. But we might swap gears depending on how our testing goes.
Send those heads up to Ed Curtis and you will see some vast improvements. Did you step up to a 1.7 rocker by chance?

 

[axeman]

hey todd, how's it going? haven't talked to you for a while. yeah, i heard you sold your car and bought bob cosby's. that's awesome. looks like you'll be even busier now huh?

well, the power my car is making is not really comparable to yours. damn near everything's stock, even the roller rockers. hopefully i'm going to be putting new rear upper and lower control arms on next weekend. bills helping me since i never played with pinion angle before.


so what do you think about the gears, 4.30's?

 

[StangFireman]

I think unless you go to a 1.7 rocker, you might want to go with 4.10's. The 1.7 will give you a little more top end. And the 275/60 is 28" tall. I don't think the 4.30's would hurt you that bad, but I'm a newby to this FS stuff. LOL

 

[PURESTREET5006]

Alot of the guys in F/S run 4.30 or 4.56 gears with the dragradial setup in those cars.....4.56 would be my gear of choice.

 

[Mike86Stang]

Depending on where your car falls on it's face RPM wise depends if I'd go with 4.10's or 4.30's. If it doesn't stand on it's face until 5500rpm + i'd say do the 4.30's with the larger tire.

Mine was dead at 5k with the stock heads...now with the mods, I relly want 4.10's if I don't go turbo.

 

[axeman]

i would definatly run out of gear with the 4.56's so that's out of the question. but, i wouldn't say my car falls on it's face at all. it seems to pull hard past 5500rpms. i usually shift ~5300. if i do go with 4.30's, do you think it would hurt my times more than help? even if i did run out of gear, it sure wouldn't be by much.

 

[stanglx]

I'd go with the 4.30's. I should probably do the same but I drive my car a lot during the summer. For me the 4.30's would be too much on the highway! I'm just going to run a smaller tire instead to try to give me the extra gear.

Good luck!

 

[Michael Yount]

Why replace both the tires and the gear? Running the 4.30 with the 27" tire is for all practical purposes exactly the same as running the 4.10's with the 26" tire (50 rpm difference is less than 1%!). Why not just change the gear? Unless of course you're not happy with the 26" tires' bite.

 

[Mike86Stang]

Mike's on the nose, unless you need the extra sidewall for the launch, may as well stay with the shorter tire & some 4.10's

 

[DirtyD916]

seems that 4.30's would be a little too steep. just my opinion though.

 

[Michael Yount]

DirtyD - you have to look at the gear ratio relative to the diameter of the rear tires; both affect the effective gear ratio of the vehicle.

4.10 w/26" diameter tire= 4.30 w/27" tire = 4.56 w/28.5" tire

Traction/launch characteristics of the different size tires may vary; but from a rev perspective, the 3 examples above are almost identical. The car would have the same road speed (within 1% or so) to rpm ratio with any of the 3.

 

[cleanLX]

I was in your exact shoes 1 year ago.
I went with 4.10's and stayed with 26" tire and am happy I did.
I don't think I'd like 4.30's on the street with my 25.4" tall street radials... even 4.10's sometimes get old on the freeways.
If my car was a track only car, or very limited street use car I'd have gone 28" tire and 4.56's, but it's not, it's a play toy and most times a daily driver.
If you are staying with bias plys the 26" tire on 15" rim should give you more than enough bite, especially if you are going to address the suspension. If you are plaing on running F/S with DR's you should likely go with the taller tire and deeper gear.

Best of luck.

 

[PURESTREET5006]

i would definatly run out of gear with the 4.56's so that's out of the question. but, i wouldn't say my car falls on it's face at all. it seems to pull hard past 5500rpms. i usually shift ~5300. if i do go with 4.30's, do you think it would hurt my times more than help? even if i did run out of gear, it sure wouldn't be by much.

Well if you can't handle 4.56's then 4.30's will be to much as well I think you should try the 4.10's before you step up to the big mans gears and if you wanna street drive everyday 4.10's might be good for you.

 

[PURESTREET5006]

DirtyD - you have to look at the gear ratio relative to the diameter of the rear tires; both affect the effective gear ratio of the vehicle.

4.10 w/26" diameter tire= 4.30 w/27" tire = 4.56 w/28.5" tire

Traction/launch characteristics of the different size tires may vary; but from a rev perspective, the 3 examples above are almost identical. The car would have the same road speed (within 1% or so) to rpm ratio with any of the 3.

Hey Yount!!!

Whats my ratio now..You know our class rules so here's what i have

4.56 & 26x10x15slick on a 15x10 rim.

 

[axeman]

Why replace both the tires and the gear? Running the 4.30 with the 27" tire is for all practical purposes exactly the same as running the 4.10's with the 26" tire (50 rpm difference is less than 1%!). Why not just change the gear? Unless of course you're not happy with the 26" tires' bite.

my et streets are just about finished anyway, so now is a good time to change tire size if necessary. wasn't really sure what would be the best answer (gear wise). i run 28" street tires, so i wasn't really concerned about stepping up to a 4.30 gear if it would benefit. but it looks like i should just stay with the 26" slick with a 4.10 gear? so why would people even run a 4.56 gear with a 28" slick unless for maximum traction purposes? seems to be a wash if you ask me.

Well if you can't handle 4.56's then 4.30's will be to much as well I think you should try the 4.10's before you step up to the big mans gears and if you wanna street drive everyday 4.10's might be good for you.

i do street drive the car alot, but it's not my only vehicle. so gearing it up is not too much of a concern to me. i'm just curious as too what would be my best decision.



thanks for the replies guys.

 

[StangFireman]

Personally I like the 28 over the 26 for better sidewall flex on launch. You could go 28 and 4.30's.

 

[perkys stang]

Mark.... I got a friend with some good 4.30's for sale if you decide.......

 

[Mike86Stang]

All about traction my man, if you need to soften the hit to the slicks on launch get the bigger tires with more gear. Where are your 60ft's these days? Having any problems hooking with the tires/launch your employing now?

 

[axeman]

bill, if the price is right i just may be interested. i'll talk to you. the more i think about it, i may be alright with the 4.30's and a 26" tire. i should cross the line ~5600 rpm. if i'm not happy with that, i could step up to a slightly taller tire since mine are on their last leg anyway.

mike, i wouldn't say i'm having traction problems but, my average 60" is only low to mid 1.8's. i'm not really happy with that. i'm putting new upper and lower adjustable control arms on very soon, so that should help alittle.