Would 4.11 or 4.10 be too much for my stock car? and what series carrier do I have?

 

Too much in what sense? Lots of people run 4.11's in 'stock cars'. My second car had them installed when I bought it, and there was quite a difference. It will affect your cruising RPM's but with the 6 spd it isn't a big deal IMO unless you are cruising the highway everyday for extended periods of time.

 

I would not hesitate to put 4.10's in an M6 car. When my Formula was relatively new and the motor still "bolt on" plus nitrous, I swapped in a Strange 12-bolt with 3.73 gears. They were "OK" but I wished I had gone for the 4.10's. With the M6's steep 6th gear O/D (0.50:1) I think it would actually improve the ability to use 6th for cruising the frreeway.

 

M6 GU6 3.42:1 is 3 series.

 

Ive heard that stock m6's with 10 bolts can shatter the rear

 

they can shatter with stock gears too... well atleast snap the axle like me

I love my 4.10s although they are in a 12 bolt

 

So, If I am crusing at 1600 rpm's in 6th gear hitting 70 with 3.42 gears what would 4.10's be reving the engine at to cruse 70mph? is there a way to figure this out on paper?

 

2100 RPM's at 70 mph with stock size tires.

 

Is that calculation off your car? I have 275 40 r17 811 revolutions a mile. What are stock,

 

I have 275/40/18 and is around 2100 at 70 also.
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Are you guys using a stock tach? Alot of them read 200-300 rpm's higher then what your really reved to.

 

I've been considering the 3.73 vs. 4.11 gear change in my M6 Z28. My car is FAR from stock though and have a friend that had 4.11 gears in his car and he told me he wouldn't go with the 4.11 gears due to my higher HP. When he had 4.11 gears he said 1st gear was nearly useless like a "granny gear" and all he did was make him shift constantly. He went back to 3.73 and was much happier. I may split the difference and see if I can find a set of 3.90 gears. I don’t do much freeway driving personally so thats not an issue for me.

 

Not at steady state cruising.

4.10's were one of the first mods I did to mine. 2100 or so is 70mph with stock tires. 275/40/17's for mine. It made the car totally more fun to drive and just seemed like it should have come from the factory that way.

Best MPG I got was 29mpg with the 4.10's and stock cam. Did that going to Memphis97 doing about 70-75mph the entire way.

It also knocked off .3 sec. off my ET, that's always a plus

 

http://f-body.org/gears/

 

The tach in my 94 typically read 100-200RPM above actual engine RPM under ALL conditions, idle, steady state cruise or WOT. That's comparing it to the PCM RPM reading on a ScanMaster.