I have a 2.75 center section (9in. ford) I was wondering what you guys thought, do you think the 2.75 is too low. the 3.55 ran the same as the 4.86 on motor but was faster on juice I dont care if the 2.75 picks up as long as it dosent slow down the road manners would be killer! and a top end beast

 

2.75 is a highway gear. It won't have any low end accelleration. Think 18 second 1/4 miles and probably barely get out of second gear in the 1/4 mile.

With 2.75 gears, the engine will be just above an idle going down the highway. It will increase the top speed especially with an OD. Land speed records are done with gears like that. You could easily have a 150 mph car on the highway but it would suck at the dragstrip.

Typical street/strip gears are in the 3.50 - 4.10 range. Higher than 4.10 and taller tires (over 26" tall) are needed or the engine will need to go way over 7000 rpm to run a 1/4 mile. 4.86 gears will be fun on the street but with that much torque multiplication, it will be easy to just spin the tires and not go anywhere. Highway driving even with an OD and 28" tall tires will be well over 3000 rpm at 60 mph.

 

i ran some 3.31 in the 1/8 and crossed the line at 6000 in 2nd
bought some 4.10s crossed in third at 5500 and ran the exact same time!
i installed 3.08 and slowed down 2 tenths and 4.56s ran same as the 3.31/4.10 only spinning so they woulda been faster

 

Thanks for the info, where are you in NC fast72ss

 

I think the 3.50 is a good all around gear with a short tire and your combo doesn't need alot of gear but 2.75 would be way too high of a gear for 1/4mile racing. The highest I would go would be 3.20's and then you will need some torque. I run real close to your #'s with a 3.42 gear 7.19@97mph 1/8th mile. 6.80's spinning alot on a 150shot. I am about to put a 8.8" Ford rear in my car and some more suspension goodies along with a set of 3.55's to try and get into the 6.30's@105+mph (which is about where you are running) and 9.90's@130+mph with a 200shot in a month or so. How much n2o you spraying and how many cubic inches? weight? LMK Later Clint

 

I am running a 406 with dish pistons. The best I've run is 7.09 on an excellent track day but normally I run 7.19-7.22 N/A. I have been as fast as 6.58 on a 100 shot on an excellent track day. I weighed the car last week. It weighed about 3520 with a 1/4 tank of gas. I turned the juice up to 175 and chunked a 9" center section. Without a 2 stage or a controller I have been reluctant to go above a 100 shot. I am just looking for a higher gear b/c I drive this car on the street quite a bit but I don't want to sacrifice track time.