1lt1wiz

iTrader: (1)

what gear 373 or 390 in 94 z28 lt1 for street and is a aluminum drive shaft worth it

jim ravencraft

Hi,
i would go with 3.73 to keep power/torque/rpm range in check.
To tall on the gears and you run out of rpm's before going into lights.
Tire size will also have an effect on your overall ratio. Check out wallace racing calculator to compare and judge for yourself. Best of luck with the install. Have a blessed day............jim

ZONES89RS

iTrader: (25)

3.90 with a 28 inch tall tire, 3.73 with a 26 inch tall tire.

Tobias05

iTrader: (1)

I'd go with 3.73s since you have an A4.

Aluminum driveshafts seem to be balanced better and save you a few pounds. My 3rd gen rode smoother at highway speeds with the AL DS.

But...from a strength standpoint you're better off saving up for aftermarket.

ahhwataday

iTrader: (7)

What gear do you have now? If you have 3.42, you should go 3.90. Anything else Id say 3.73 but either way you should be happy. Really all your personal prefereance

justin hover

Their was somewhere I read about how 3:90s were not good for a4s awhile back, Something different about whats involved in the install and it wasn't good, can't remember but that's why I went with 3:73s and love them

slo2pro

what rpm are you at on the freeway?

justin hover

With 2:73s I had before I was running 1900rpm at 70-72mph
With 3:73s I now run 1900 rpm at 55-57 mph...and 24-2500rpm at 70 mph.
It was a fair trade off, and with running alittle higher rpms your / atleast my exhaust sound 2x better, and it feels 2x faster by far

garygnu

with small cubs run the 3.90s,with bigger cubs or power adders run 3.73.look at tire/rim rotating weight.

ahhwataday

iTrader: (7)

They install the same and require the same rebuild kit. You may have read about the difference in teeth size, 3.90 are weaker. Something else should break before the ring and pinion in a 10 bolt tho.

Slash8915

iTrader: (21)

I have 3:73's and have no problems.