Rear gear choice for P51 combo

This is for a 1/4 mile drag only 92 mustang hatch with ladder bar setup on a 28x10.5 slick , weighing 2700 , running a C6 ,8.8, the converters going to UCC this week for a restall , the motor combo is a 552 , 14to1 , P51 heads, mafia intake, 1250 quick fuel, custom solid flat tappit, 276-286 @.050 689-668 lift , it has 3.90's in it now, what would be the right gear for this combo for all motor ? I was thinking 3.73 but want to know whats worked best for you guys plus Lennys going to need to know.Thanks,Bryan.

For best results N/A I gear for the max rpm I want it turning when I cross the finish line.

cool40 wrote:For best results N/A I gear for the max rpm I want it turning when I cross the finish line.

X2 what is your finishline RPM, and is NOS in the mix.

back several years ago my 552 n/a motor was similar with a PG and 411 rear gear in the 1/4 the rpm was around 7400 on 28's.if I remember the time was 9.40@141 @ 3200lbs

I think Lem said about 6700- 6800 for that motor combo would do it.

Should peak around 6700ish. Probably shift at about 7100-7200 IMO

Do you have room to grow the tire...if you do you could keep the 3.90 and increase the tire size if it is not optimum , if not you could go to the 3.73 and if it is too much you could shrink the tire. What MPH are you looking for 160ish

Whats it crossing at now? If you aint run this setup yet i wouldnt change it before i did.

cool40 wrote:Whats it crossing at now? If you aint run this setup yet i wouldnt change it before i did.

X2

This is a new setup and it will be a new converter, so we'll try it with the 3.90's first then.

nuclearcobra wrote:This is a new setup and it will be a new converter, so we'll try it with the 3.90's first then.

good plan, that'll give you somewhere to start.

I bet the 3.90 is gonna be damn close

Well that's good to hear then, makes it a little easier

I ran my 557 with a 28 x 10.5 with a 4.10 gear for 1/8th mile. It turned 7750 through the 1/4, ran 9.0s 150 mph. I would say the 3.90 will be close.

Mine will go through the finish line @ just under 7100.
572"/P51's, 33" tire, 4.11 & the car weighs 2500#