43-tooth purple driven speedometer gear
Thread Starter
Joined: May 2012
Posts: 437
Likes: 115
From: Arcadia, OK
Car: 1990 Pontiac Firebird Formula
Engine: L31 350 TPI
Transmission: Tremec TKX
Axle/Gears: 3.23 Posi
43-tooth purple driven speedometer gear
Anyone know where I could buy one of these? I recently swapped out 2.73 for 3.23 and went with the supposedly correct 17/44 speedometer gear combo, but my speedometer is off almost 5 percent. 43 tooth should cut that error in half (if my calculations are correct).
Joined: Jul 2000
Posts: 6,520
Likes: 91
From: Aridzona
Car: `86 SS / `87 SS
Engine: L69 w/ TPI on top / 305 4bbl
Transmission: `95 T56 \ `88 200-4R
Re: 43-tooth purple driven speedometer gear
It's 5% slow at 60mph?
If yes, proceed with that 43.
But also see if mile markers and your odometer agree over a 10 mile run.
If it is 5% fast, you need a 45.
If yes, proceed with that 43.
But also see if mile markers and your odometer agree over a 10 mile run.
If it is 5% fast, you need a 45.
Supreme Member
Joined: Oct 2004
Posts: 4,526
Likes: 238
From: Henrietta NY
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
Re: 43-tooth purple driven speedometer gear
Our speedometers are not always accurate. I would use GPS with your phone to confirm before taking anything apart.
Thread Starter
Joined: May 2012
Posts: 437
Likes: 115
From: Arcadia, OK
Car: 1990 Pontiac Firebird Formula
Engine: L31 350 TPI
Transmission: Tremec TKX
Axle/Gears: 3.23 Posi
Re: 43-tooth purple driven speedometer gear
Did three 60 mph timed runs over three mile section; averaged 3:086, so the speedometer is 4.7% slow (indicated 60 mph is ~57.2). Admittedly this isn't horrible, but it kinda bugs me. If I can't find a 43-tooth gear, won't be the end of the world. Just thought I'd check and see if anyone had one laying around.
Supreme Member
Joined: Oct 2004
Posts: 4,526
Likes: 238
From: Henrietta NY
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
Re: 43-tooth purple driven speedometer gear
Did you use GPS or the internal odometer to measure the miles?
Thread Starter
Joined: May 2012
Posts: 437
Likes: 115
From: Arcadia, OK
Car: 1990 Pontiac Firebird Formula
Engine: L31 350 TPI
Transmission: Tremec TKX
Axle/Gears: 3.23 Posi
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