MeanWS6

this will go behind at 408ci, 3.73 gears, transbrake with 4000 stall and a 200 shot. Is it worth it to upgrade to the 2.75? Will this make driveablity without OD "better." Will it help when foot braking when spraying or will I get too much spin.
I read that the 2.48 bogs HARD on launch.

ATVracr

iTrader: (5)

I'm getting the 2.75-1.57 upgrade on my th400 coming from Coan soon. I have a 346 H/C and will be hitting it with the 200 shot also.

I dont see how it would hurt drivability, still 1to1 in 3rd thats all that matters really.

B18B1LS1

iTrader: (12)

Your car won't bog with the 2.48 if your running a 408 with a 200 shot out of the hole. I would rather save the money and go with the 2.48 over the 2.75, and it will be easier to hook.

Big Mike

iTrader: (4)

You guys should stick with the 2.48. The 408ci motor plus the nitrous will make so much torque, then add the multiplier of a 2.75 1st gear and you'll never hook and if you do, you'll wish you had whellie bars on the car. I highly recommend you stick with a 2.48 1st gear!!

john kilgore

you guys that are going to order 2.75 will have to be patient l won't have any for at least a month.

nuzee

iTrader: (2)

Going to a wider gear spacing can hurt you at the track by putting you outside the powerband after a shift. Closer gear ratios can be a benefit because it allows you to cam for a shorter more intense powerband. Then you dial the rest of your setup by choosing the right rearend gears & tire size. I'm sure you guys understand all of this already. I'm posting this for those that may not realize it.

Pro Stock John

iTrader: (34)

Stay with the 2.48, not worth it for you.

Tim98TA

iTrader: (7)

The 2.75 is also weaker that the 2.48

john kilgore

plenty strong,and in special orders can be made with 6 pinions or 8 pinions

ATVracr

iTrader: (5)

Do you work for Coan?

john kilgore

l do not work for dave, we are just friends and buy stulff from each other.

distortion_69

iTrader: (20)

Sorry to bring this thread back from the dead, but was just searching.

Would the 2.75 be better for a turbo car to help it get out of the hole considering the low compression and lag? Especially on a larger turbo such as a T-88, or T-76.

Thanks,
Josh

James B.

iTrader: (1)

Not really, no. What you need for a turbo motor is a torque converter with a high stall-speed. For the turbo you need to be able to bring the RPMs up in a brakestand to spool up the turbo. While standing still gearing has no affect on this ability - it's the torque converter letting it happen.

TwnTrboCE

iTrader: (43)

Turbos make a ton of tq. Espesially ones with big cube motors. We just went to a 2.10 gear in the Formula to make it easier to hook. Also turbos like to be under load. You put these things together and it makes for a fun ride.

distortion_69

iTrader: (20)

I'm running stock cubes, so I know it won't be quite as ridicolous off the line as a 400+ cubic inch motor. However, the tranny I'm considering does have a transbrake, which should get me leaving pretty damn hard regardless of the first gear ratio.

Thanks a ton the advice,
Josh