8 3/4 rear engine dragster gear ratio

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keith340

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i have a mopar 366 dragster,weighs approx 1800 with me in it,comp solid roller,5k stall,jw 2 speed trans,12.5 compression,rhs prepped indy x heads,750 quick fuel carb,msd ignition,victor 340 intake with a 1 inch spacer, im running heads up 1/8th mile, i dont want to turn it tighter than 7 -7500 at the finish line, what gear ratio and tire size do you guys recommend? any help is really appreciated
 
Have you tried one of the many online calculators that use, tire size, weight, hp etc ? They have been pretty helpful for me.

Pat
 
Only been around that type of car in the 1/4, but i'll make some wild assumptions. :)

8.70 @ 150 roughly converts to 5.50 @ 123. that's gonna take a mid 5 gear with a 31/32" tire.

It'll take a little over 500 hp to run that #.

Imo, probably could use a little more carb & converter to be all out if your peaking in the 7k ish range.
 
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Looks like the most readily available low gears for the 8.75 are 5.13's. While that may not be optimum, that should easily be in the ballpark. I assume this is a rear engine car so a 30" - wide tread tire "may" work if you need to get the rpm up. If that's competitive, so be it.

While i'm not a fan of riding a converter most of the race, running the 1/8th to full potential with a PG will require a high stall.

My friends car that i made test passes in was a 350" Nhra C/ED, PG that left on the brake at 6700 and shifted at 7500. That car ran 1 hun off the national record in the early 80's.
 
iirc, been 40yrs, the econo class was much like a S/S engine, stock block, b&s, heads, comp, with any cam and intake. The "C" class was limited to any 750 cfm carb. The car went 9 teens with a 302 & low 8.90's with the 350. I see no reason you can't eclipse those numbers with modern technology.
 
I really wanted to learn more about this car's combo, rules it's going to run under, etc. Oh well, guess that's not gonna happen. :(
 
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