I have a 1979 f100, 521 stroker, built C6 transmission full manual reverse Valve body 2800 stall converter with transbrake, 35 spline 9 inch with Detroit Locker that currently has 3.89 gears. 295/65r15 Mickey Thompson ET Street radials. in the quarter mile rpms are at 5 to 5200 rpms, should I drop the gears to 3.70's or even 3.50's? Will that hurt or help my 1/4 times?

 

i dunno i have always heard useing 4.10 or 4.11s for track use, but smaller may help the RPM. not the best with gears my self my buddy knows a lot so i will talk to him, one big thing are you trying for better times or better MPG- basicly tell me what your looking for.

 

I had a good chuckle on that one .

 

I am no drag-race guy, but I would think that you'd want to be at redline when you cross the finish line. How many shifts are you making on the way down the track? If you had taller gears, could you one less shift? That might be good.

 

I couldn't care less about miles per gallon I want to have better quarter mile times

 

better MPG for a 521 stroker is probably impossiable, but not for a regualr engine, i know a guy that gets 20 MPG with a chevy 454 w/ 400 hp in a 55 BelAir wagon, all due to the gears in the axle.

 

thinking on it now it would be pretty hard would'nt it

 

Did you have your engine dyno'd? That would really help you if you new pick HP and Tq. If not, what is your max RPM you will go to? I drag raced and built chassis almost 30yrs, you most likly wont want to go lower than a 4.10, 4.56 would help your 60' times but im afraid you may run out of RPM's at the top end. Or are you only running the 1/8 mile?

 

I had the truck dyno ed put down 375 rwhp. Max rpm around 5500. See that's what I'm afraid of is running out of rpm's. 1/4 mile track up in Colorado at 5800 ft.

 

Food for thought. What speed are you planning on reaching in that 1\4mi? And what is your rev limit? Now use that in a formula to figure it out. If you know your current rpm vs mph vs gear ratio you should be able to crunch that.

If you are hitting 5100+- rpm now and you want a max of 5500, I'm not sure you have much room to play with.