I just bought a 2008 Mustang Gt and the speedo was off and so I had been trying to figure out why and it came with a tuner and so I decided to tune for gear ratios and got to 4.10 and now the speedometer is correct.. at 70 mph in 5th i'm right at 2400 rpm, 80 close to 2800-2900.. first gear is also EXTREMELY short. so I was wondering if any of yall think that sounds like 4.10s before I take the time to get out in this 100+ degree weather and jack it up to see.
4.10s at least. I think American Muscle has a rpm table on there sight. Look up 4.10 gears and I think it's on that page. Doesn't seem like I'm quite that high at 70. But I'm going to say yes to 4.10s.