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1996 roadmaster
LT1 with Hot cam, 3.73 gears, 2400 stall torque converter

I don't really like 3.73 gears and decided to change them to 3.08 or 3.23 to get them more usable on the highway. 3.73 were turning too high RPMs at highway speeds. Plus MPG is not that good.

I want either 3.08 or 3.23.
Question is, will these gears work well with the 2400 stall lockup I have now? With 3.23, I will only hit 2500 at 85MPH so does that mean it will never lockup until that speed?

Or does it mean that if I move to 3.23 or 3.08 I will also have to upgrade the TC to 1800 or 2000 stall?

mark8ish

I think your fine. The 2400 refers to what rpm your engine will spin up to before the converter puts power to the tranny. Your converter will actally "flash" higher than 2400 rpm if you floor it. The converter will lock up when the computer tells it to, the 2400 has nothing to do with it. In the 1/4 mile your converter wouldn't lock until just before you crossed the finish as the power transfer is better unlocked until certian parameters are met.

__________________
95' Impala SS - Headers - Cold air induction - 160 Stat - 3.73 Gears - 2200 Stall - Hypertech chipped

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That's good to know.

Steve Smith

"I think your fine. The 2400 refers to what rpm your engine will spin up to before the converter puts power to the tranny. Your converter will actally "flash" higher than 2400 rpm if you floor it. The converter will lock up when the computer tells it to, the 2400 has nothing to do with it. In the 1/4 mile your converter wouldn't lock until just before you crossed the finish as the power transfer is better unlocked until certian parameters are met."

Did you drag race your SS in stock form to get a baseline figure? Based on your experience, what direction do I need to go to get my Roadie wagon into the 14s RELIABLY ?
What's your best drag results with your Impala?

RMC

My advice is to step down to 3.42 if you really want less rear gear. I think that lower will be too drastic for you. Going from 2.93 (or lower) to 3.73 was a huge change for you, but I think that going back that far will not make you happy. I had a '91 9C1 with factory 3.42 gears and it was a great combination. (An LT1 would have made it even better!)

I am wondering if the TC would feel a little sluggish with the lower gears. [It should be ok with the 3.42 gears.] When I had my trans rebuilt, I had him put in the highest stall "OEM" TC that he could get, about 2000 rpm. My car does feel less powerful (or maybe more subdued) on slow takeoffs, but a little faster on a hard launch. I have read posts about people that have put higher stall TCs in stock geared cars and have not been satisfied.

You said that you have a hotter cam. That usually means that it has more top power at the expense of some low end torque. We have heavy cars and low end torque is a good thing. We compensate for this with higher gearing and higher stall TC's to still take advantage of the high end horsepower gains. Giving back too much gearing will hurt your car's performance on the low end and not get the full advantage of the top end.

mark8ish

I haven't taken my car to the track yet as it was my only ride and I don't trust these trannies to take much punishment. I had the same tranny in my 99' T/A and that's why I traded for the SS I have now. If you go to "drag times" you can see what results people get and what mods they have if any. I would think with some good rearend gears and a professional tune you would be in the 14's. I have a 2200 stall from a grand national and it is really hard to launch without smokin' the tires. LS1 engines produce hp at high rpm so a 3000+ stall is great, but for these stock LT1's I would go for a lower stall as they are made to produce lots of low end torque. I'll post my numbers when I go to the track this summer.

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95' Impala SS - Headers - Cold air induction - 160 Stat - 3.73 Gears - 2200 Stall - Hypertech chipped

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Interesting points you make and just what I suspected.

3.08 is a bad idea, it's the stock gear in SS anyway.

How about 3.23? I had that gear in a 93 wagon with towing (every towing package got L05 + 3.23 gears) and was pretty happy with it, it's a good gear for highway and snappy in town. It should be even better with cammed LT1.

Going from 3.73 to 3.23 should reduce my RPMs by 300 at all speeds. My MPG is abysmal right now, under 18. Plus if you have to drive 70+ mph, the engine is just too noisy.

I am aware of pre-94 9C1 getting 3.42 gear... That was with L05. Now with the newer 9C1, the LT1 9C1 got 3.08 and the 9C1 with the smaller engine which was L99 (4.3L) got the 3.23 gear ratio. Of course the station wagon is heavier than the sedan, so I think (hope) 3.23 might treat it well?

Dwayne J

A stock LT1 likes 2800-3200 stall just fine, yes they make nice torque but that should not stop you from staying really low on the stall. When I had a 2800 Edge in my car a gearhead passenger mistook it for stock in town, I "corrected" him with my right foot when we got to the edge of town.

Modern QUALITY high stalls drive well and don't make much heat.
I have a 3800stall Edge in my sedan right now and at a 900rpm idle it pulls against the brakes harder than my wife's bone stock '03 Impala does. Also have issues keeping the tranny warm enough. If I hotlap it like 3 passes in a row at the track I can get it to just crest 200degrees(still safe) but that is back down by the time I get to the timeslip booth.


IMO the OP had issues with the car, a few guys are unhappy with 3.73s but most love them. For a pure highway car I like 3.42/2800, drove that for awhile before a deer sent me in another direction with the car. Totalled it so I bought a wagon to drive while I fixxed it which lead to having two cars so I could modify the sedan more heavily.

__________________
Dwayne
96 Caprice with AI 200cc package
Best et 11.5
Best MPH 116
Just another taxi

RMC

ETC... Why did you start a new thread and just ask basically the question?
Anybody like 3.23 gears?