89IrocZ350TPI

Now I know the reason that their was never an L98 5-speed was because the trans at the time couldnt hangle the torque of the 350. BUT why was there never a 350 that came stock with 3.45 gears? Why put 2.77's in a performance car? The 89 iroc z L98 ran a 14.8 stock. If it had 3.45's stock it would probably have hit 14.4's.

Orr89RocZ

iTrader: (20)

they had 2.77's and 3.27's. I think the reason was for gas mileage purposes and the simple fact that a L98 fbody with the 3.45's would rival the Vette's of the same years in performance. GM couldnt have that. Else L98s would be very close to breaking 13's bone stock

p.s nice avatar

Burnout91

Don't forget 'emissions per mile'....my car went 14.3x with just a set of 3.73:1s. -Bill

89IrocZ350TPI

Yeah I think the G92 cars got 3.27's. Still 3.27's isnt a while lot better than 2.77's on a TPI car. I have also heard from others [now yourself] that it was because the Corvette of 1989 ran low 14's, which is where 3.45's should put a stock L98 car.
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How did you like the 3.73 gears with tpi? Probably would spin the tires off the car..

avro206

gas mileage. I don't buy that the 3.45s would have put it too close to the Corvette at all-----hardly a difference between 3.27 and 3.45s (Camaros still heavier and auto only)

Orr89RocZ

iTrader: (20)

yeah i did the 2.77 to 3.27 swap and although the car felt faster from rolling starts and such, i only was able to match my best ET on street tires and 2800 stall. I did pick up a mph or 2 on average from the swap. 96.6 to 98 or so. With a set of slicks i'm sure 3.27's were worth a tenth to a tenth and a half. But the 3.42's i have now in the 10 bolt, it felt like it picked up alot. Just still hard to launch on street tires with more and more gear.

the difference for me between the 3.42 and 3.27 was more than the 3.27 and 2.77's

89IrocZ350TPI

3.4X gears are probably the best all around for TPI. You should try 3.73's now that you have an HSR setup..

Orr89RocZ

iTrader: (20)

3.70/3.73's would be perfect for 1/4 mile times with HSR on a L98. Even most head/cam setups will like it alot.

I now have a 383 HSR that wants to rev up alittle, so i need to get me some 3.73's or in a perfect world, 3.90s to get my car to run its best. I will hold on to the 3.42's for the time being

Burnout91

Stock G92 option on my '91 Z28 5.7 Auto was 3.23:1 axle ratio. Spin the tires off of the car with 3.73s?..........does "Burnout91" give you hint? It spun bad with the 3.23s too...!-Bill

89IrocZ350TPI

Hey I just read your profile and I was wonder what is your rwh? I cant see the graph its too small, and also what do your 1/4 times look like?

Burnout91

RWHP peaked at 4750 RPM, 321; held 300rwhp until 5500 RPM. I haven't had the car to a track with the current mods.
Bill
P.S.: If you look for a thread in the So Cal forum titled "ThirdGen Dyno Day", the dyno graph is also posted there.

89IrocZ350TPI

Cool. I have a similar setup as yours, and I am currently looking for a good head/cam match. I want to have around 300wrh and run mid 12's. Pretty much where you are at.