I have a 1998 F-150 4.6 V-8 and I want to know what is the best gear ratio that will give to most power out of my engine.

 

Gears ratio dosn't make or give power.
It multiplies whatever torque output the engine makes at any given rpm.
For example if the engine is making 100 lb/ft of torgue at 2000 rpm and your in third gear, a 1 to 1 ratio; with a 3.55 rear gear ratio the torque is 100 x 3.55 = 355 lb/ft of torque.
In overdrive the torque is cut by .23 from 355 to 273.34 lb/.ft.
Another way to express this in OD is the take 3.55 x .77 = 2.7335 final ratio x 100 lb/ft torque = 273.34 lb/ft of torque applied to the tires.
The last part of this final torque is the tire size effects.
The results of lower rear gear ratio is to multipy torque but at the expense of higher rpm for the "same" road speed in mph. This higher rpm will also use more fuel overall.
The answer to you question is only answered by what you want to settle for.

 

Good answer Bluegrass-
I changed from the stock 3:55 to 4:10.
This works for me as I am looking for beter performance (acceleration) and fuel economy is not important.
I do very little freeway driving - but this is where the lower gears really showup as a negative.
Where my truck would previously tach 2,000 rpm at 65 mph or so, it now tachs 2,500 rpm at 65 mph... more or less. I
I am in effect wearing out the engine faster.

Lower gears do give you more torque to the ground, but if you are looking for better overall performance, a better starting point would be a chip or programmer. Everyone here is pretty happy with the Xcalibrator2.

 

im thinking about gettin some 4.10's lol my truck falls on tis face in 3rd but then again im fighting alotta wind to lol

 

Don't you mean a lot of "hot air"?

 

what about 4.30's? I have a 4.6 and I am contemplating this route, what do you guys think

 

I think 430's would keep you off of the freeway all together...kidding.
It's not as big a jump from 355 to 410 (15%) as is 355 to 430 (21%).... if you have very tall tires, it might be ok.
You need to make sure what you have before you can estimate the effect of a change.
I have 31 inch tires - taller than stock & 410's, and I like it (13%)... but at 70 mph I can feel the motor winding more.

 

ok well I have stock tires is that to much or am I gonna be ok?

 

if you do alot of freeway driving and have stock size tires then go with 4.10's.
with 4.30's you'll be really happy with the performance of the truck but you'll eventually dread any highway trips because of the bad mileage you'll get.

i have 35" tires on my truck with 4.56 gears and it's not too bad on gas as long as a i stay at 70mph or less. at 90 mph+ the fuel guage goes down fast but the power is sure there.

the original question was which gear set would give the most power out of the engine and to that i would answer 5.13's or even higher. this will give the most power out of the engine to the rear wheels to push you down the road. how much you want to spend on gas and the top speed you want you truck to drive at is a different story.