First off let me say that I did the T56 change over, it use to be a 4L60E, thats why I have a 3.23 gear. I have the 94+up one with the 2.66 first gear.

So how many mph should I gain going from the 3.23 to the 4.10?

I would like to hear from people who went from the 3.42 to 4.10 as a base but I would probably gain slightly more. What are we talkin about here maybe 2-3 mph in the quarter?

 

I know a few guys that drove on 4 30's and even riding in the car at 90 the rpms werent bad at all.

 

Can't comment on track gains but I scanned a friends 97 with t56 and 4.10s, highway rpms are still very low thanks to the .50 OD, and the acceleration with his cam is almost violent. The only and I mean only posible downside to 4.10s is going to be they will keep you a little more busy in town, other than that(and that is not bad) they seem to be a great match to the t56.

 

My t56 is a changeover as well, and I still have the 3.23 gears in. I drove a friend's SS the other day that has 4.10, and I couldn't believe the difference in WOT shifting, it was like as soon as I shifted into gear it was time to shift again immediatly, the tach went almost no where. I'm really torn between 3.73 and 4.10 at this point, I think 3.73 would be a nice change from the 3.23, but I don't want to regret it and end up getting 4.10 anyway. By then it might be time for a Moser anyway thought

Tell us how it goes!

 

See I know what you mean about the decision. I think a 4.10 and a set of radials would be killer but brutal to the rear end. The 3.73 sounds like a good compromise. I would really like to get a 3.90. I've heard a few people talking about them but I have no idea where anybody sells them.

I think the 3.23's are too small. You burn your clutch on daily driving and bog more than you should on drag launches.

4.10's might be too big for street tires, even with 275/40/18's. With the 4.10's your going to be tached out at about 110mph at the most. If you throw maybe even a small shot of nitrous your going to be running out of room.

3.73's should make it easier on your clutch during daily driving, while not taxing your tires as much and still allowing for quick launches without the need for drag radials.

I'm just curious. I would like to ride in a car with 4.10's first before I made my decision.

 

Yeah it's a big difference when you're used to driving in a 3.23 M6. Especially on the highway, i can do 80 and not be just under 2k rpm, but in the 4.10 car, 70 is 2k.

I'd be very interested in finding a 3.90 for our rears. I just don't have enough money to be dropping on a new rear anytime soon

 

I don't think they make the 3.90 for our rears! I' pretty sure those running that gear are either on a 12 bolt or a 9"

I too have a 94 with the M6 conversion and the 3.23 rear end. I had a rear with 4.10's in it(bought it used without pulling the cover) when it was an auto and it had a tooth missing on the ring gear. I also have a 3.42 rear that's got some searious bearing noise going on (this is why I'm still running the 3.23) I installed the 4.10 rear end to see how it felt with the M6. It was the most fun day and a half I've ever had lol. One really good shift from 1st to 2nd took care of the rest of the teeth on the ring gear and a couple on the pinnion lol. I could be in 2nd taching about 2500 and just break the tires loose at will, it was loads of fun. I have 3.73's I need to put in sometime soon. I got them for a really good price, some are telling me I should sell them and get the 4.10's but I think I'll be happy enough. I guess time will tell

 

So a 3.90 is the only thing you don't have!?! hah

 

Hey when you say you could light the tires up "at will", what tire are you running? That depends alot. When I had my stock rims and tires I could burn them "at will" even with the 3.23 gear. I put on the 275/40/18's and now even with more mods it won't burn them unless I pop the clutch. Probably because they are wider and are slightly larger in diameter. Maybe 4.10's would be better for me since the larger diameter knocks the ratio down a few numbers. I just hope I can get traction if I'm careful. Anybody running 4.10's with a larger than stock size tire?

 

I would say the only downside to 4.10's is the fact that you will run out of gear in the quarter. It runs out of steam (even with my cam) at like 111. So if my car gets any quicker then i will have to shift into fifth gear before the end of the quarter mile mark.... Just a thought. But I do love my 4.10's!!! LOL.


Chris

 

I was running 245/40/18 on a 9.5" rim. there wasn't much sidewall flex in those things! The car only has the usual bolt ons, CAI, Flowmaster, 1.6 RR's, hollow cat, Acell 300+ ignition

 

when i calculate it i get 115 mph on a 27 inch tire which is close to stock i think, that is at 5800 rpm's and most likely you will have a cam and will turn it to at least 6200 which should be pushing 120 in 4th, sounds like the perfect choice for a rear end gear on a stock to heads cam lt1.

 

The stock tires have a rolling diameter of 24.88"

I'm at about 6400 RPM when I cross the line in fourth gear.

If you're running taller slicks it works out fine. Even my slow *** car is running out of gear quickly on street tires though.

When choosing gears for drag use you shouldn't go by what people think is the best gear ratio. Find out what RPM you want to cross the line at and get the closest gear ratio without going over.

 

my bad i thought when i measured my 245's it was 26. something, it was a while ago