oldskool04

i just had them installed today and the first thing i noticed is that my rpms were the same as stock gears, so i got mt sct to fix that and now the rps ars lower than the 327 i had in there. i also feel no dirrerence in performance. the guy said in about 400 miles tobring it back after they are broke in and he said he will reshim it something like that. is this normal i got the gears from jegs what is the reasononing for all of this. i am very frustrated if this is all 4;10S DO

black35th

Are you sure you had stock gears to begin with?

Mustang_NTriangle

U would see a night and day difference with 4.10s vs. 3.27 stockers even if you don't get on it. You have much more tq down low. Did you keep your old gears? How many teeth are on them? It seems to me that you probably already had gears in your car or the guy did not put them in to begin with.

BraMas

What Ihave never heard "bring it back and I will reshim" Like already stated do you have the gears they puled out.
Count the teeth on both the Ring and Pinion Gears.
EX: Ring Gear = 41 teeth
Pinion Gear= 10 teeth
41 divided by 10= 4.10s

cliffyk

The engine speed in any given gear, at a givenvehicle speed should be higher than with the stock gears. What rpm is the engine running, in 5th gear, at 60 mph?[/align][/align]With 4.10s andstockdiameter tires it should be around 2050 rpm...[/align]

mikemc04gt

Hmm, I had stock 3.27's replaced earlier this month with Ford Racing 3.73's and I can tell a difference. The car runs about 300 rpm higher in 5th gear at 60 mph and accelerates better in every gear.

boduke0220

wouldnt that suck if you already had 4.10's?

oldskool04

he gave me my old gears the have 327 on them. with them at 70 i was about right at 2000 now at 70 im at 1800 what the hell is going on. i programmed it in with 410 and in a 35mph speed limit it says im going 50 but cars are passing me. im so put out at this point

cliffyk

[/align][/align]If the tach is reading 1800 at an indicated 70 mph in 5th, then the PCM is programmed for something around 3.08gears; not 4.10s.[/align][/align]Here's a quick way of getting close to what gears you have (assuming stock diameter tires):[/align][/align]Divide the rpm at 70 by 586.6[/align][/align]It doesn't matter whether it's the actual speed or what the speedometer says. Ifit's theactual speed (measured with a GPS or whatever) this will tell you what gears you have;[/align][/align]Ifit'swhat the speedometer saysthe result will be what gears the PCM is programmed for;[/align][/align]In your case, 1800 / 586.6 = 3.0685, 3.08 is the closest gearset.[/align][/align]=====================================[/align]The 586.6 number is the result of multiplying 811 (the # of revs/mile of the OEM tires) times 70 (mph) to get wheels revs/hour at 70 (56.770 rph); [/align][/align]Divide that by 60 to get wheel revs/minute at 70 = 946.17 wheelrpm (at 70);[/align][/align]Now multiply the wheelrpm by 0.62 (the 5th gear ratio) to get the constant 586.6 which is the wheel rpm to engine rpm relationship excluding the rear-end ratio.[/align][/align]586.6 timestherear-end ratio = engine rpm;[/align][/align]engine rpm / 586.6 = gear ratio;[/align][/align]piece of cake...[/align][/align][/align]

jmac72187

Something is definitely wrong with that situation. You would notice the difference the first time you drove the car.