Question about gears
 

Does anyone know who makes 3:90 gears? I saw them somewhere before but can't remember where. Also I used to have an 85mph speedo but I put reverse glow gauges on and took it to a place by my house to have it changed to 140mph but it's still 5 mph off, so if I get a 3:90, or end up getting a 3:73 what should I do to make the speedo accurate?

memories
 

Not sure but I think the 3.90 gear was used in 60s era Fords with the 9" rear end (like the Boss 302). I don't think this rear set is available for the 87-93 generation Mustang with the 8.8" rear.

For the 87-93 year Mustangs the speedo is set accurately (supposedly) by changing the drive gear in the speedo cable where it meets the transmission housing. These speedo gears are refered to by the number of teeth on them. I think the 23 tooth gear is for the 3.73s.

If you're saying that reinstalling the old speedo without a gear change still resulted in 5 mph error, you've got something else going on there. don't know.:(

Actually the Ford 9" differentials had a 3.89 ratio, but that's not available for the 8.8's. Basically your ratio choices are 3.55, 3.73, 4.10, 4.33, 4.56, and 4.88.

I have for sure seen 3:90 gears for 87-93's they are brand new

Do you know who makes them? I know Richmond and Ford Motorsports don't. Maybe Zoom?

Somebody does because I have seen 3.90's as well.

www.motivegear.com

Andy

Anyone know if they make good gearsets? The 3.90's seem like a good size, I'd just hate to put them in and have them break/be noisy.

I knew I saw them somewhere, Pro 5.0 has them