Hey guys, I finally have the funds to get my gears installed...I have a set of FRPP 3.55 gears...I am looking to get a little extra punch out of it, but I want to keep nice highway mileage. For an extra $100 I can have the shop install 3.73 FRPP gears. I don't want to spend the money on getting my 3.55's installed and end up being unhappy with them, but I don't want to get 3.73's to see my highway mileage take a nose-dive.
What kind of RPM do you guys turn at about 65-70mph?...3.55's or 3.73's just trying to get an idea.
Thanks,
Don
automatic or five speed! my auto is at 2100 at like 65-70
i say go with 4.10s they were awesome when i had them!
Well seeing you have the ho all ready go with the 3.73s,you will like the get up and go.
The only problem is,since your using the t-bird aod you will not be able to get a speedo gear to get it accurate,the biggest ford has is a 21 tooth and you would need a 23 tooth(they don't work worth ,aftermarket).
If you can get a stang trans then you can use a 21tooth and it will be dead on.
Rpm with 3.73s at 60mph are about 23-2500rpm on the hwy.
at 3000rpm i'm pulling around 140-145kmh.
Yeah, my car is an auto and I dont' want to go as big as 4.10's. I plan on going with the 3.73's now if I can afford to have them repack the clutches in my traction-lok. As far as the speedo recalibration, according to others, I should have the 7 tooth driven gear in the trans in which case the 21 tooth will be fine.
What trans are you using????
Stang or t-bird???
If you have the stang trans it will be 7 if you have the bird or coug one it will be 8 no question.
Okay, well then I've been misinformed...I made the appointment for this Saturday morning...the guy told me that the 23 tooth goes so much faster because it's a softer plastic...he says the guys usually come in once or twice a year for new ones. I'll have them install one and I'll buy a spare while I'm there.
I wonder if I'll be able to burn the tires into 2nd a little instead of just a good chirp. :fart:
I feel like a kid before Christmas...counting down the hours...I simply can't wait and feel like I'm going to jump out of my skin(they should have a smiley depicting that).
3.90's
you should be able to anialate the tires in 2nd, chirrp 3rd np. mine did. id stick with the 355s if you already have them though....
What's the story behind Stangs getting a 7 tooth drive gear and 'Birds/Cougs getting 8 tooth. are the AOD's different overall length? Tailshaft (the one with the drive gear?) different lengths? Otherwise would it be possible to swap AOD's or tailshaft assemblies without changing drive shafts? Just curious since I would like to swap to a trac-lok 3.93 with least permutations of changes as possible.
OOPs meant: 3.73 with least permutations of changes as possible. must be getting late.
Well, I just got my gears done...feels much different already...and I have to baby it for the weekend to let it all break in. The guys who did the work(Performance Specialties, Inc. Pottstown, PA) were awesome...very friendly, didn't mind me talking to him while he worked or watching him. I had the gears installed and had the clutches in the traction-lok replaced/packed. With the gears, speedo recal, $45 shims, and repacking the clutches, it would have been $557 and change...but I got a $200 parts credit.
They also installed a 21 tooth speedo gear because it was all they had...my speedo is off by almost the exact same amount as it was before below like 40mph...after that, it's only off by 1-2 mph from what it used to be.
They told me not to use any friction modifier in it with the packed clutches because it's kind of counter productive...they said expect the inside tire to chirp around turns for a few days...lol.