Just wondering what size gear i should order for my nine inch for my 1987 regal. Will have a 500 horse small block on nitrous and putting a built 200r4. Running quater mile tracks and will have the talllest widest tires i can fit under the stock whell wells. Will have the overdrive for the street and highway but what size gear? Im thinking 4:10 or 4:30 but with an overdrive should i go to a steeper 4:56? Is that to much gear for quarter mile?
What size gear to buy?
- Thread starter Dmax Cody
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if you plan to use this for street, I would say a 3.73 is plenty with 500hp... My 3.42s work fine for street/strip.
But if you're more into strip, then 4.10 is good... Not an expert, but 4.56 seems excessive...
But if you're more into strip, then 4.10 is good... Not an expert, but 4.56 seems excessive...
I'm working towards a similar set up except I'm hoping for close to 600hp without nitrous regardless i think a 4.10 would be perfect it would get you across the stripe at about 7000rpm or so in drive depending on how tall you tire is exactly, and you would still have the .67 (i think thats what it is in the 200 4r) overdrive to run around on the street and not have to turn excessive rpm. just out of curiosity are yu running slicks and if you are how wide and tall are they? i have a 78 regal and i still need to buy tires and such along with a bunch of other things and i want to get the biggest i can withough cutting anything
M.Bailey said:
I'm running 27x10-15s, but they are too wide, and too short... You may experience otherwise,
apparently 28x9-15s are ideal for our cars. I've also seen as tall as 30" and wide as 10.5" without notching or cutting.
Is this going to be a strip car you occaisionally drive on the street or a street car you can take to the track? Your suspension makes a lot of differance. A car with street suspension and 4.10's might have problems hooking.
Personally, I'd go with 3.42 or 3.73 to keep from blowing the tires off at the line and let your HP and torque carry you across the line.
If it's mainly a strip car , then I'd probably go with the 4.10's. A good strip car will likely have better suspension to help plant the tires. You want your engine close to the HP/torque peak as you cross the line.
Personally, I'd go with 3.42 or 3.73 to keep from blowing the tires off at the line and let your HP and torque carry you across the line.
If it's mainly a strip car , then I'd probably go with the 4.10's. A good strip car will likely have better suspension to help plant the tires. You want your engine close to the HP/torque peak as you cross the line.
Hopefully that is a strong 200r.
You guys are forgetting the 200r has a 2.75 first, that with N2O is a bad combo with such high ratios, 4.56 :shock: .
You should be in the 3.23 to 3.55 area max.
Heck my NA Pontiac motor has a custom 2.10 since it makes so much torque ( like a N2O motor will) along with 4.10 gears.
My 2.10 x 4.10 combo has less effective ratio the a 2.75 x 3.55 set-up.
I am going down in ratio to 3.89 this year.
Your torque convertor should match peak torque, threw the traps about 300/500 rpm after peak HP.
You guys are forgetting the 200r has a 2.75 first, that with N2O is a bad combo with such high ratios, 4.56 :shock: .
You should be in the 3.23 to 3.55 area max.
Heck my NA Pontiac motor has a custom 2.10 since it makes so much torque ( like a N2O motor will) along with 4.10 gears.
My 2.10 x 4.10 combo has less effective ratio the a 2.75 x 3.55 set-up.
I am going down in ratio to 3.89 this year.
Your torque convertor should match peak torque, threw the traps about 300/500 rpm after peak HP.
What kind of rear do you have?? I have a 514 Hp 388 stroker and I recently had a 700-r4 installed in place of the th-400. I biought a set of 4:56 gears and sent then to the transmission shop as well. My transmission guy called and said with the 1 st gear in the 0/d transmission he would go with 4:10 vs. 4:56. ( had 3:73 in her ) Now that I have the car back, glad I listened to him...BTW, when you buy Summit brand gears, they are actually Richmond gears.....even have their stamp on them....
For his basic question only and for the benefit of other readers, stop guessing, first use online power to weight calculator for best possible mph in traps then pick the gear with tire height that will get you as Shotgun said thru the traps at about 300/500 rpm after peak HP.
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