[DiamondJim]

My combo: 463/400rwhp/11.72/1/4,3800lbs race weight. Made peak hp right around 5400. I raced 1/8 mile for the 1st time last note, with the 3.73's I am shifting right before the traps. Seems like all the tracks are going 1/8 mile now. What kind of rear gears are you 1/8 mile racers running? Anyone have a calculator link that might help? Thanks -Jim

[se428bandit]

Jim did you run at Lagrange or reynolds.

[DiamondJim]

Hey, I ran last night at Atlanta Motor speedways Friday nite drags, they run 1/8 mile. I ran at Reynolds a few weeks ago. Reynolds has Saturday braket racing(1/8) mile, I like running there but it is 110 miles one way. 1/8 mile feels strange, it just feels funny shifting to 3rd and then the race is over. I have a set of 4.10 gears I might swap in. I lost last nite to a 70's era Vette with a 502 by about a car, the 4.10's might make up that much? I found out later the guy had run in the final the week before. -Jim

[DiamondJim]

BTW, I am a lot closer to lagrange, it is about 50 miles. Lagrange runs 1/8 mile too I think. -Jim

[92GA]

We ran my sons 81 bird a couple years ago with 1100 x 29 Hoosiers with 4.56 gears and shifted @ 5400, went throught he traps @ 5600. That's with a th350 trans and a 406. Last year we went to 5.13s and shifted @ 5800 and throught the traps @ 6100 or 6200. We picked up 2 tenths going to the 5.13s The car runs mid 7.20 with my son driving and mid to low teens with me, but 60 fts better with him. I'm putting the engine and trans in a 96 bird now, and will be using the 5.14 but going with 32" tall tires. IF I ever get it done for him.

[DiamondJim]

I am runnig a TH400 w/10" Continental, stalls about 3600, solid cam, pulls well to 6000. I already have some 4.10's but I am thinking for the 1/8 I should use about 4.56's? I plan to stick with the trans/converter/28" tires for time being at least. Just looking at the situation, unless someone opens a 1/4 mile track nearby, I will be racing the 1/8th(I really prefer the 1/4). Should I try the 4.10's or buy the 4.56's? How much would be gained by going from 3.73's to 4.10's or to 4.56's? You opinions are appreciated. -Jim

[92GA]

If it's a track only car, I'd gear it to run the track you race at. Dought if you would see much differance going from 3.73s to 4.10s. But 4.56s are a bit much for the street. I run a 5.43 with 32" tires and a th350. I shift at 6200 and trap 6400 with my Grand Am. I broke the side out of the case last Sunday, destroyed the 9" ring and pinion. I'm going back with a 5.67 or a 6.00 and a pro case this time. Haven't made up my mind yet

[WDCreech]

DiamondJim, In the September 15, 2006 issue of DRM (IHRA mag), there is a chart that gives a conversion of 1/4 mile to 1/8 mile gear ratios for maximum performance. It doesn't list 3.73s, but it does list 3.70, and it says the best replacement for the 1/8 would be 4.63. If I were you, I would go for the 4.56s or, if you want to press it, 4.88s.

[DiamondJim]

Thanks WD, I was already leaning toward the 4.56's. Now for the next question, for my low hp car which gear set should I use? I have been running Richmond street gears and they are the cheapest(165 at Summit) but I see US Strange has what they call Pro Street gears for 238 bucks, OR should I upgrade to the Pro Gear? The Strange gears say they are 8620 steel but the Richmond doesn't say what it is. Thanks -Jim

[92GA]

I ran richmond 4.56 street gears in a 8.5 10 bolt, with 29x1100 hoosiers with no problems. But I have also seen guys destroy 8.5s and 12 bolts. Depends on how they are setup. My biggest problem was axles. The case on my ford 9" let go last Sunday, not the pinion support. So they can all break. I would go with the 4.56s also.

[DiamondJim]

I have Moser axles, tubes welded to housing, Ford bolt on ends. I am running Richmond street 3.73's now, that is probably what I will get for the 4.56's, unless the US Strange would be a lot stronger. -Jim

[stimpy]

racing gears are made from a softer material to handle the sudden shock of taking off the street gears are made of a more durable material for long life (harder) , we use a set of 4:56 richmonds street gears in our 8.5 housing( T/A girdled) under a 3500 pound car with 650 hp big block other brand motor launching at 35-4200 off a trans brake and they lasted 4 years ( till someone decided to change the yoke out and didn't replace the crush sleeve) I would call US gear and see what they recommend .

[mels80ga]

Jim,
Unless you are loking for optimum performance, I wouldn't change the gears. If you are going to bracket race it doesn't matter as long as you are consistent. I won yesterday running 7.82 - 7.86 for 7 rounds with 1.77-1.78 60's on a hot track all day. Just find a set up the car likes and will be consistent with. I run 3.73 gears behind a 406 in a 3400 # car, shifting at 5200-5400, and I shift into 3rd gear at about 500' or so, hard to tell cause by the time I am there I am looking for the other guy.
Mel

[DiamondJim]

Thanks Mel. The Friday Nite Drags deal is run heads up 1/8, that is the reason I am considering the gear change. I lost last Friday(by about a car) to a guy that ran in the championship. It is kind of goofy but fun, the starter drops his hands like Pinks! The race is run on the pit road at Atlanta Motor Speedway. I am running Domestic, (Mufflers/etc). There is a Hemi Dart there that is fast, the guy that beat me has a 502 Vette. Also the next 2 closest strips to me have gone 1/8 mile, I really don't drive my car more than a few miles on the road, so the gear change will be OK. -Jim

[DiamondJim]

And oh yea, CONGRATULATIONS ON YOUR WIN!!! -Jim

[mels80ga]

Jim,
Thanks! We run the street drags the same way on Tues. nights. I went out one time and ran. It is fun, we do ours off the flag also with 6 heads up classes, including bikes. I mainly went out to let my son ride with me down the track, we made two nitrous passes. On one of the nitrous passes we ran a friend of his in a late model SS Camaro, and pulled him by about 300'. My son really got a kick out of that and we had a good time. Going to steeper gears may also create traction issues. Either way the main thing is to have fun and enjoy your car!
Mel

[DiamondJim]

Thanks Mel, traction will be next, I was spinning out of the hole Friday already, lowered my MTETDR's to 16 lbs and did a John Force crowd pleaser burnout and hooked pretty good. Only 3 trips to the track and the tires tread are about 1/2 gone! I am running 2 air bags/no-hops/HO Racing rear sway bar/adjustable uppers, etc. I will probably install an anti-roll bar this winter and remove the sway bar. The guy with the 502 Vette that beat me told me he had 5000 in suspension mods so my changes are a bargain-LOL. I hung with him all the way down the track, the 4.56's should leave him in my mirror(I hope). I sure wish I had installed a 9" rear, all this gear changing stuff would have been a piece of cake! Oh well, live and learn. Have a GREAT day! -Jim

[Cliff R]

Jim, what ET and MPH are you running with the current combination? I've went 7.20's at 95 mph on our local 1/8th mile track. Just happend to be pitted beside a guy running a gutted out Nova with a high compression 454, 4.56 gears, loose converter, etc, and he was only running 7.10's at 93mph. He liked to crapped himself when he wandered over and found out we were running a pump gas 455, q-jet/iron intake, full exhaust, 3.42's and a tigtht 10" converter......and DOT's!

I really don't think you'll pick up much with the taller gearing, and it could make the car even harder to hook? Then of course, you'll really be revving hard when you find your way to a 1/4 mile track......Cliff

[DiamondJim]

Cliff, no 1/4 mile tracks left around here. You can run sportsman at one but it stops at 12.0. Usually run 7.30's/7.40's in 1/8 at 93 or so. There are some really fast cars hooking the MT's I am running, we shall see. I am saving my 3.73's, I will have 3.73's,4.10's and 4.56's, (4 series carrier). If we had a good 1/4 mile track I would get a 3 series carrier and run 3.42's but the 1/4 mile tracks are disappearing! I can run the Friday nite deal and then run Sat afternoon if I feel like it, both 1/8 mile. I know my suspension will have to work to pull this off, we shall see. I almost feel like putting in 3.23's or 3.42's and test your Powerglide theory! BTW, do you shift to 3rd in the 1/8? My 2/3 shift is about 200 ft before the end. Thanks -Jim

[69Goat1]

I agree with Cliff on this - I changed to a 4.10 from a 3.73 for the 1/8th mile stuff and slowed down a small bit... The car likes to torque it's way down the track, since we also have a great 1/4 mile track nearby I am going back to the 3.73 because I think it will run better on both tracks...