Just a general question....

If everything on a car stayed the same for both applications....one with 3.73 gears, and the other with 4.10 gears, how much of a difference would there be in pull? Just generally speaking....I know other things have to be considered. Also how much of a difference is there between 4.10 gears and 4.56 gears?
Has anyone made either of these swaps?

Thanks for the help guys.

More information is needed. Engine, cam and tire size. 4:10's need a very tall tire or a very high reving engine as a general rule.

I made this change and my car slowed down 1/10 of a second. 4.10 gears had my car crossing the finish line at an rpm that was well above my peak horse power curve. I kept the 4.10s and switched to some taller 29" tires. This brought the finish line rpm back down to 6100 rpm. My nitrous passes were faster due to the fact that engines on nitrous prefer lower gears.

(4.10 rear gears)

26" tire pass - 100 shot of nitrous - 11.67 et

29" tire pass - 100 shot of nitrous - 11.49 et

I like using the taller tire as it has a bigger foot print and increases your mph. Taller tires also aid in traction. If you switch to 4.10s you may want to use a taller tire, otherwise keep the 3.73s.

Alright.....I guess it's kinda a pointless question. Sorry for asking. I mean I know that tons of variables need to be considered...ie. trans, engine in general, purpose, tire size....etc. I was just curious if the difference between the gears is very significant/noticeable. I understand the whole gear size/ratio deal.....but I was just curious if anyone had made the switch/or was using those gears, and how they like them. I know many people use 3.73's because of they're pretty much good all around. Does anyone on here use 4.56's on any of their street/strip cars?

I calculated out the sort of RPM's I would be running with the combo I have and different rear end gears......just wondering what you guys prefer for your cars.

thanks

There's a lot that has to go into this, but generally I have used an RPM range as a guide.
{Using 275-60/15 tire 28" tall as example}
5500 RPM engine 3:55 - 3:73 gear
6000 RPM engine 3:73 - 4.11 gear
6500 RPM engine 4:11 gear +

Depends on how hard you want to run it and what is your purpose.

IMHO and experience,steep rear gears (over 3.73) are over rated and not required with most street/strip cars.

tongue.gif , mines a bit steep for just cruising around, but man what a blast !! TORQUE MONSTER !!

damn scott....those are some high (numberically) gears! What do you guys think about this combo...

Engine
327 .040 over
Balanced/line bored
forged pistons (maybe nitrous up to 150 shot)
10:1 comp
steel crank/stock reconditioned rods
Performer RPM heads/ performer intake
600cfm edelbrock electric choke
headers/ 2 1/2" exhaust
gear drive (not sure who by...came with car)

turbo 350 with b&m shift kit & 2K stall (later M21 or M22)

rear end
275/60/R15 (or R16)
ford 9" with...

3.90?
4.11? or
4.56? gears

The purpose being to build a fairly streetable drag car. Something I can take to drive 40 or 50 miles to the strip if I want to.

The way I see it is the car could handle the higher RPM's while driving on those extended trips.

What do you guys think?

them there 3.90's would probably work just fine for ya ;)

My first 4 gears a are equivilant to a 5.05 rear gear, but then 5th goes back to a 1:1 and its an old 4.10 gear again. :D

My 67 chevelle has 4.10 in it from its racing days still. With 275 rear tires it runs about 3200 at about 60MPH. I would opt for the 3.73 gears if U plan on driving it on the street for any distance or freeway 65/70mph. 3.73 gears should drop RPM's to about 2800. I dont have to drive the car far works a mile and a half and its never been on freeway. Its fun to drive with the 4.10's and mild 396 ( 9.75cr, balanced, crane 278/290 529/525, stock cast holley intake, holley 650DP.). I run the motor to 5200RPM. I have a 3.31 12bolt posi waiting for spring, wanted a 3.55 but price was right on the 3.31. Will keep the 4.10 rear for the 427/454 motors im putting together now (500HP 3000-6000 RPM range)

Originally posted by supersport6667:
My 67 chevelle has 4.10 in it from its racing days still. With 275 rear tires it runs about 3200 at about 60MPH. I cruise around at about 35mph at 2900rpm, with 275/60/15's on the rear. But man it's fun !! :D