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Author Topic:   3/8's gears
7x racing
Dirt Roller

Total posts: 7
posted June 03, 2002 10:35 PM
hey guys, i'm new to the forum. i'm running a street stock on a 3/8's mile track with medium banking. i'm running a 355 flat top motor jr motorsports with a hydralic cam. I'm also running a saginaw 3 speed tranny and the rear end is a gm 10 bolt with a 2.73 gear ratio. this weekend i ran the car in first gear to about 5400 rpm's. I was needing to know which rear end gear would be best with the 3/8's track and my combination. i have been told that 650 to 700 final gear ratio would be best combo.thanks in advance
7x racing]http://www.thedirtforum.com/ubb/smilies/cwm12.gif[/IMG]

[This message has been edited by 7x racing (edited June 10, 2002).]

rcf5r
Dirt Roller

Total posts: 9
posted June 03, 2002 10:44 PM
sounds like a pretty low gear for 3/8 track i run 5.43 final gear still run about 7,000 r.p.m

racer17j
Dirt Forum Champ
Total posts: 1565
posted June 04, 2002 01:11 AM UIN: 54865418
what are you running for a rear roll? most guys here will run from 6.20-6.33 with imca 9/1 motors mid 80's tire roll

DEEDDUDE
Dirt Maniac

Total posts: 111
posted June 04, 2002 06:42 AM
With a sag. 3 speed no-line in first and a 2.29 rear your final would be 6.53. I run this on a 3/8 track w/ 88" RR. I turn 6500-7000. Same trans with a 3.73 rear gear running in second gear will get you a 6.30 final.
Which 3 spd do you have? let us know and we can figure out the rear gear needed. Good Luck.

ryan
Dirt Freak

Total posts: 430
posted June 04, 2002 12:34 PM
Does anyone know the rollout of a dot legal 235/70/15 on an 8 inch rim thanks

7x racing
Dirt Roller

Total posts: 7
posted June 04, 2002 01:23 PM
i have the "no line" saginaw 3 speed. i believe 1st gear is 2.85, 2nd is 1.68, and 3rd is 1.00. please correct me if im wrong.
thanks,
7xracing

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7xRacing

merlinmech
Dirt Full Roller

Total posts: 51
posted June 05, 2002 09:07 AM
I run a 3/8 with 5.43 @ 6300 rpm. What track are you running?

Scoot
Dirt Freak

Total posts: 330
posted June 05, 2002 08:38 PM
7x that is correct.

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Scoot
Smith Racing Team
870-365-5989

Pickel
Dirt Forum Champ
Total posts: 564
posted June 05, 2002 08:50 PM UIN: 25419780
I run a 538 and cranked about 5800..this year I have 543 that I am going to start with and may go to a 567. I also run a 3 speed Saginaw in third gear with 235 60/15 street tires.

7x racing
Dirt Roller

Total posts: 7
posted June 05, 2002 08:51 PM
i run a 3/8's in NM. A super stock racer who is a consistent winner at this very track recommended that i run a 650 to 700 final gear ratio. He is very knowledgeable when it comes to chassis work and his car proves his knowledge. i really want to get this gear thing figured out, i'm fairly close to making a gear change, you guys have been a bunch of help! thanks,
7x racing

[This message has been edited by 7x racing (edited June 10, 2002).]

Scoot
Dirt Freak

Total posts: 330
posted June 05, 2002 08:59 PM
7x I'm currently changing from a 7.06 to a 6.26. Mainly to help tire spin and lower rpm's. The higher the rpm's the harder it is on your motor. If your going to run that low of a gear make sure you are using the best parts. Or you'll be like I was tearing up stuff.

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Scoot
Smith Racing Team
870-365-5989

merlinmech
Dirt Full Roller

Total posts: 51
posted June 05, 2002 10:19 PM
Gotta agree with scoot there. But if the guy winning is running that deep, it's probably pretty close. If you can only afford one set, get the higher set. Like scoot said it's easier on engines. And its easier to drive. The biggest advantage you will see with the deep gear is on a heavy track.

tilley88
Dirt Freak

Total posts: 353
posted June 06, 2002 12:45 PM
If you were running the trans in first, then you should've been crankin serious rrrrrr's! You must be runnin really tall tires or your timing could be tarded. Find a vega 4-speed(triple ringer) and match up with your 2.73 rear, will give you a final of 6.74. I've run that on a short, tacky 3/8 track and it's good with a big motor(6200 rpm). I've also run 7.10 final with a small motor at the same track, and turned 6800 rpm. This is with 88" Hoosier tires.

7x racing
Dirt Roller

Total posts: 7
posted June 06, 2002 10:52 PM
Hey guys! thanks for all the replies. What size of tire do u think i should run. last week i ran 275/60s in the rear and 255/70s in the front. i have a tire sponsor so changing the size of the tires should not be a problem. i want to run between 6000 and 6500 rpms in first gear. changing the size of tires will be a temporary solution until i can get time to make a gear change.thanks guys!
7x racing

ray14
Dirt Full Roller

Total posts: 67
posted June 09, 2002 09:50 PM
hey man we run 3/8 high bank and in our 9" we run 6.50 or 6.33 gears using 3rd in tranny tire size we use is 275/60 on rf,rr,lr 245/60 on lf for stagger hope this helps o yea we turn about 6100 rpms

[This message has been edited by ray14 (edited June 09, 2002).]

tyler weiss
Dirt Roller

Total posts: 13
posted June 18, 2002 11:19 PM
I would say about a 5.67 to a 5.83 in 3rd.

7x racing
Dirt Roller

Total posts: 7
posted June 19, 2002 11:11 PM
hey guys i found a ford 9" housing with axles w/disc brakes for $300.00. For the $300.00 i'll also be getting afco leaf springs and sliders that are originally on the car. i was thinking about getting a third member from midwest motorsports for $409.99. Do you guys think it would be financially wise to purchase the rearend.
thanks,
7x racing

p.s. the housing is in great shape.

racer17j
Dirt Forum Champ
Total posts: 1565
posted June 20, 2002 02:00 AM UIN: 54865418
i sure would if it's all set up and all you have to do is bolt her up as for buying a new gear look around at some other sites and find a used one save yourself a couple hundred bucks if you go to imca.com the classifieds they have all kinds of gears on there all the time for about 250-300

Pickel
Dirt Forum Champ
Total posts: 564
posted June 20, 2002 09:37 PM UIN: 25419780
I agree with racer17. I bought my gears off of a guy that had a post on racingjunk.com and I got a great deal. Imca has a lot of good deals also.

HIGH VOLTAGE
Dirt Full Roller

Total posts: 37
posted June 23, 2002 06:14 PM
7x go with the 9" ford rearend,6:50 gear and run the trans. in highest gear.This will put your gear ratio 1:1 gearing your car through the rearend insted of the trans.This will free up some extra horses.This is what we ran on 3\8 tracks.Hey it worked well for us three back to back championship seasons.Good luck

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