I think you're gonna love them. You'd better get a lot of seat time with them before Sal's, cause you know we can't go to the track w/o running head to head at least once. Gotta give the crowd another good burnout show.
To keep this simple, I am going to say that our cars stock run 68 mph at 2000 RPM in 6th. That would be 34mph/1000. Since gears are linear, the 1:1 4th gear would be 21.42 mph/1000 with the stock 3.55's. This would yield 139.2 at 6500 RPM. If we change to a 4.10 ratio, the 6th gear is 29.44/1000 and 4th is 18.55/1000 yielding 120.6 mph at 6500. 4.30 gears yield 114.95 at 6500 (17.68/1000). So, it appears that for most folks, 4.30 gears would be too short unless they want to shift to 5th (not recommended).
3.90 gears would be 19.5/1000 in 4th and would do 126.7 at 6500. One could argue that, with smaller pulleys that work mnost effectively at lower RPM's, a high performance 03 would do better with 3.90's since a 120 trap speed would be 6150 rpm. This is about how high you want to rev. The same trap speed would have the 4.10's at close to 6500 and the 4.30's gasping at 6800 rpm.
While your experiences may vary, it is apparent that if you want to use the 4 speed, there is a limit to the gears you should run. Of course, the .8 reduction to 5th is not that bad, so, you could run all five gears if you had the tires and the drive train to handle the power, but you'd want shorter than 4.30's for a 500 HP Cobra.
There are no mathematical accidents at science central. But, for those with less HP, the 4.10's may work. 3.73's are another possibility but, since they only give a small advantage over the stock 3.55's, they scarcely seem worth the $400 to put them in. They would do 5890 RPM at 120 in 4th.
Remember, this is an exact calculation but it is based upon our cars doing 34mph/1000 in 6th stock. Still, it should be close enough.
way to go tetge, can i send you my algebra 2 hw?:rolling:
i had a detailed discussion brian from b&d that while 3.90s seem to be the ticket, ford racing does not make a set of them. richmond, know for their rear gears, does make a set but are supposed to howl at speed. so has anyone found a good set of 3.90s???:shrug:
I am leaning towards 4.10's from Ford for that very reason. Leaning very heavily, I might say. In fact, my car does not seem to be in the garage right now. I wonder where it might be? You can blame that damned Juan for this mod!
George has 3.55's. But, at LACR you shouldn't be over spinning your Eaton. Of course, George seems to have a lot of HP and he was not running drag radials. I still think that drag radials hurt your top end rush for some reason.