I've got a 93 Z28 M6 with subframe connectors, aftermarket exhaust (Installed by the prior owner, so I'm not sure which one), and a K&N air filter. It's my daily driver, but I do enjoy driving it *big grin*. I was thinking about changing the rear end to 4.10. A friend of mine said that it'll drop the top speed a lot, screw the clutch, and lower the gas mileage. I'm looking for technical reasons why he's right or wrong on these points.

Thanks in advance for the advice!

-Lucas

 

I don't think you will like 4.10's with a stock motor.

Rich Krause

 

your friend is mostly right except for that clutch part i dont see many probs with the clutch your gas mileage will drop for sure especially on the highway as for top speed well im sure you can still pull 160 mph out of a 6 speed if you got the room.BUT you friend forgot to add one other problem and its a pretty big problem with 4.10's traction from a stand still the second you hammer it to wide open trottle those tires are gonna smoke not like little squeal but pretty much half way through seocnd gears making launches really hard to control unless you put drag radials on but if you do that wave bye bye to that rear end.you should be a lot happier with 3.73 gears. they are not as extreme

 

I've heard that the '93 T56's work better with 3.73's than they do with 4.10's because of the gear ratio differences.

 

ive heard that even with a stock Lt1/LS1 6 speed 4.10 gears will make your car ice skate through 3 outa the 6 gears even with its stock amount of torq but i dunno thats just what i heard if u do go 4.10's dont forget to use some drag radials like nittos 555's or something

 

I had 4.10 when before I had a cam swap, and they worked much better after I had the cam, you just shift to earily with those gears and a stock cammed motor.

If you plan on reving higher later, then go for it, but for under 6000, you would be better off with 3.73's.

 

'93 M6 came with 2 different transmission ratio's - if you have the model with the higher ratio then 4.10s will be to much for the street.