Im building a 70 Nova 3200Lb's,402LS,PT91,28"tire.Built 4L80 trans with a transbrake that i can take off in 1st or 2nd.Im looking to have a very fast street car im looking for it to hook as good as possible on the street for racing but not lag or blow the tires off,will have a boost controller.What rear gear would work best since i can take off in either gear on the street 3.25 or 3.50 ? What you guys think ?Im leaning toward the 3.50 but i dont know ????

 

3.23 or there about is the best choice, imo

 

Anyone ???

 

Are you going to race only or street/race. What mph do you think it will be at going through the traps? Converter slippage is another big factor. Whats the highest you want to spin the motor?

 

I agree. I"ve run 273 in my turbo Fairmont for awhile they work great too.and I had 323 's in my trans am with boost worked awesome.

 

3.50 for a street car with 28" tires.

 

Street/race is what im gonna do,no track around.Gonna spin the motor to 7200ish.No idea what mph i will be going ??

 

4.11/4.53 need all the torque you can get lol

 

Kent STOP !


I see everyone is thinking 3.25,im just thinking since i can take off in 2nd on the trans break than maybe a numerically higher gear like atleast 3.50 to 3.75 ? Am i wrong ???

 

Personaly to me its not going to make a difference. I"ve went from 273 to 373 on boosted cars it makes it feel stout outta the hole but that's bout all it did. Some guys might say different but ive had good luck with high gears in turbo cars.

 

The higher gears (numerically lower) you have you better have a stout torque converter, otherwise you will just blow through it.

 

That's very true.

 

3.70 here.
maybe going to 3.89

 

HOLY what rpm through the trap

 

I agree. Street races need to end by 150 which is about 7000 depending on converter slip. I'd love to be able to go to a 3.2X gear but I don't have overdrive.

 

So your saying if you did have overdrive you would do like a 3.25 gear ?

 

Turbos like engine load so taller gears are preferred (3.25 etc) and superchargers respond better to deeper gears (3.73 or shorter) to get the crankshaft speed up so the supercharger gets into its powerband. The taller gears will help with traction too.

Holley EFI has a traction control option that is pretty slick from Davis Technologies. If you are serious about putting down the power... I would look into that as well. A 91mm turbo should easily put you in the mid 8's.

 

Cool Thanks man

 

I got the 3.25's coming thanks guys

 

I use 3.25's now in my setup and the turbo loves it, converter not so much but it is what it is. You should be happy.