LUVTruck.com

between rear gear ratio. i still need to be able to drive on the street but on the highway i dont want it to be screaming, for all street id go 3.73 and all race would be 4.11. so would 3.89 is what im thinking. in a ratio calculator it puts me 200 rpm below 3000 at 60mph. im fine with that. but how will 3.89 do at the track? am i going to lose quite a bit in the 1/4 mile?

How can anyone answer this without knowing what you're driving?

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'83 Isuzu P'up Diesel LS - Original Owner
JoeIsuzu@IsuzuPup.com
IsuzuPup.com

There is not enough difference between 4:11 and 3:89 to make the swap the least bit worth the effort...

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FIAA!

SFPP!

setup is sbc383, th350, 9 inch rear. the 9 inch isn't built yet thats why im trying to figure it out so i only have to do it once instead of switching out the R&P

Tire Dia. is needed.

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Certified pilots, looking down on people since 1903.

Not knowing what the tire size is, my experience is the best compromise for street and still being able to get off the line is a 3:50 gear. Also to fine tune it you could run a taller tire on the street for the best highway rpm and something with a lower profile for the strip. In my 63 stepside I ran a 350/turbo350/3:42gear and 275/60/15 tires and it could cruise at 70 and still light up the tires pretty good off the line with a nice chirp into second.

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Three Amigos

I'll be running a 28-29 inch diameter tire.

A 29" tire will turn 695.45 revolutions per mile.
Multiply that by the gear ratio to give rpm's at 60mph with a 1:1 high gear.

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'78 Chevy LUV,1.9,4sp,headers,31's,SAS Dana 30,Dana 20,SOA rear w/Aussie Locker, rough body, bought new 12/4/78.
'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.

Exactly....I have run several different gears in mine. There is no "perfect" set up for street/strip. On the hiway there is minimum change in RPM at hiway speed unless you are changing a full 1.0 in gear change....but a nice thing about a 9" is up can swap chunks and have several ready to stick in if nessary....

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Money can't buy happiness, but it can buy horsepower...and that's kind of the same thing...

whats your induction?

whats your converter stall?

whats the trans built like?

suspension?

all factors for choosing gear, especially if your trying to be competitive.

for the average joe schmoe build? a set of 3:42 to 3:73s are the most fun on the street.

A.j.

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http://www.youtube.com/watch?v=ykgDNjeTa0g

whats your induction? 770 holley, dual plane weiand stealth air strike

whats your converter stall? 3000-3200

whats the trans built like? th350 hardened intermediate sprag, hardened intermediate roller

suspension? stock rear springs with caltracs and stock front suspension, will be changed to coil overs soon

I must be missing something here as from what i read is you want a street rig that you can drag race to right?

Chances are you will be bracket racing anyway so set the rig up for the street (i would use 3.50s with the 29" tires)and enjoy in will still be fairly quick and then change gears as you get closer to just drag racing .Then you must pick the gear for your tire size and rpm at the stripe.

There are so many variables that these are just suggestions for you to ponder.

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1978 pro street step/side 455Buick, 4sp,4.11s, 31/18.5s