I have a 1988 Lariat with the 5.0, summit racing noisy geardrive, ford racing underdrive pulleys, fully custom AOD transmission w/ transco shiftkit. I was running 10.5 in the 1/8 running stock gears. I decided to put in 4.30 gears and increase my time, well that didnt happen. The last time that i ran at the track was last fall and drove the truck through most of the winter and decided to take it to the track this spring with the new gears and see how i was running. The only thing that increased was my 60' but my speed at through the traps was the same. I am thinking that i might have lost some compression or my converter is clogged. Any help is appreciated.

 

what gear did you start with? What rpm is it shifting at? waht rpm and what gear through the lights compared to last year? what tire combo? Weight?

 

..and you consider that a MAJOR problem???

how would 4.30 gears INCREASE your time, what did you have in it before?

 

your 60' time may have increased...
but its falling on its face at speed...


you may have acceleration at first but the tourque curve is way off now
too much gear my friend and not enough ooomph at high end...


...zap!

 

I agree that my tourque curve may be off. I just dont understand why in the 1/8 mile everything wouldnt pick up from changing the gears, but im kinda new at this game so im not sure. What do u think would help get the desired tourque curve back? I was thinking cam or bigger injectors.

 

unless you have very big tires . 4.30 is to much, what did you have before?

 

Or smaller gears.

 

I started with the stock 1988 8.8" f150 gears, not sure what ratio they were. My tires are 235/75/15, stock.

 

Its in 3rd gear and running 64mph through the lights. Not possitive how many rpm im turning but my i still have plenty left. I know that my truck dosnt have a verry good top end from past experience so i might need to find some ways to add some horsepower.

 

I do not understand changing the gears to 4.30's when you did not know what you took out. Maybe you had 5.30's in there already.

 

So you don't know the origional gears? Post the axle code on your door jam sticker.

Adrianspeeder

 

oh my gosh

...zap!

 

gearas are a funny thing. if you dont need them, they can actually hurt your performance.

i had 3.70 in my 383 firebird and ran a 12.80 @ 106, blew the pinion gear and put the stock 3.27 back in and went 12.70 @ 109. The 60 ft was a little slower but it made up for it by putting the power band in the sweet spot. The 302 , espesially in trucks is not the reving machine that people think thet are. The long runners promote low end torque, the reality is that by 4800 it is all done, shifting past 5200 is pointless,

your dont list 60 ft time and that is the tell - tell, it could be that the taller gears are causing the truck to spin more.

i cant see were you need anything more than a 3.73

 

There's a LOT more to top end than just HP!

Too high gearing will limit your top speed at your "red line", how much power you have means nothing.

Too little gearing will limit you in other ways, but with enough gearing hp means little, and you can move a freight train with a sewing machine motor.

You said your truck has always had a limited top end, that could be caused by already having too high gearing, especially since you also said you felt you had some revs left over...

 

easiest thing about hot roding and the track, if it dont work fix it!! changing to a super low ratio, from probaly a 3.55 or 3.08 will make your power band skyrocket, unless you have a rollerized blueprinted and balanced motor you are not going to see a benifiet from changing rear axle ratios. try puting the stock gears in. bumping the hp, with a cam and shift kit or maf and injectors or whatever else you find that will make you wallet smaller!! good luck