When installing 4:10's do you have to get a tuner? From what ive gathered, gears will throw off the speedo. And the tuner will bring it back to the correct settings? I just purchased some gears and figure if u need a tuner to dial the speedo in then its an excuse to get it dyno tuned as well!!. also are ford racing gears decent ?

 

Their are still speedo recalibrators available so a tuner isn't the only option, however 99.9 people out of 100 will get the tuner for it's adjustabilities. The tuner does come with a "high performance" tune but I assure you it isn't even noticable from the seat. The advertised power gain is 10 hp so I'm sure it's more like 5. Get the tuner and get a dyno tune AFTER you've modded the car to your liking. As for your gear question, here is some useful info. I posted after I had my 4.10 installed .................................................. .....

Wow these 4.10s are nice. For those who don't already know, many FRPP gear sets are now actually Motive or USA, presumably because of the abundance of demand, and are drastically different in there appearance (chrome instead of black) and install specs (backlash range of 3-6 rather than 11-16, I think). I never noticed it, but the part number on the box ended with "M" (for Motive) with "made in italy" printed under it. The USA "FRPP" gears part # ends with A. I have a hard time thinking Ford would outsorce manufacturing that would result in a lower quality, but in my and my installers opinion, the true FRPP gears are better because the grooves are formed by a "5 cut" process rather than the less precise "2 cut" of the Motives and USA and for the fact that installers, like the one who did mine today, are less familiar with the newer style of gear.

I've since discovered that the coating on my gears with the part # ending with "M" was from something of a pre-heating process that gives the gears the benefit of not needing break-in time and a likelihood that the gears can be reinstalled if the gear swap results in the annoying gear whine from an incorrect backlash. If you end up with the same type of gear I did, don't sweat it, just make sure your installer is somewhat familiar to this info. Good luck, and give 'em hell.

 

Thanks rygi. Yeah i never expected much out of a tuner. The car has full SLP exhaust, k&n intake, and with the 4:10's will be as far as i go until a procharger happens. So this is just an excuse for tuning it and getting it on a dyno to see the numbers. I also have an MGW short throw and the prokit. So seeing that our vehicles are somewhat modded the same i sure hope my mph will be as high as your 107 !. Really didnt think the car would mph that high. Im not gunna pretend i can run a 13.1 at the moment seeing i havent been down the track before. But i have BFG KD 315's that seem to work alright when warm on the streets. Might help with the driver error! Thanks agian

 

Your welcome. I know what you mean about wanting to get it tuned. If you haven't bought a tuner yet, find out the shop's preference in tuners they like to dyno tune with. The 13.1 @ 107...I did have an o/r H pipe at the time, before it started hanging too low, which could have yielded a tenth or half a tenth, and it was prolly the run that did in my 4th gear synchro. That run was with 3.55s and 4.10s haven't helped at all because I don't have your 315s....dammit. It's all in the tires, HEAT 'EM UP. You should run a 13.0x. If your full SLP includes longtubes I'm guessing at 308 rwhp for your baseline dyno run. Keep me posted, I'm curious.