My Camaro book says the 91 Z28 came with three possible 305ci V8, the LO3 (170Hp, which is the TBI engine) the LB9 (210HP) or G92 (230HP). I know the LB9 is the TPI motor, which I have. The Chilton repair manual I bought says that the VIN code number for the engine, which is F, means it is a 5.0 TPI. But the Chilton book doesn't mention anythinga about the G92 engine. They guy I bought if from said it was a 305tpi "HO" motor but he really knew less than I do about it. What is the G92 engine?
thanks

 

I thought G92 was the RPO# for a 3.42 posi rear?

 

Itr is a performance package, that, on trhe 305TPI, boosts output to 230(pre 91) or 240(91-92) hp due to dual catalytic exhaust, also has 3.42 posi, and4wheel discs. To get a 1LE you had to order G92 and delete AC...

 

ok, so the G92 is not really a different engine, its just a performance package, specifically what you get when you order the 1Le package right? I know I dont have the 1LE package so I must have the normal 305tpi with 210 HP. This is what I thought.

 

The LB9 G92 Package was available on 5 speeds and came with a different cam profile, AFAIK.
I could be wrong, but I am only human.

 

Seems like G92 meant different things different years. On my 87 iroc G92 stood for the 3.23 limited slip differential. I believe G92 is just a performance differential.

 

Here's what thirdgen.org's RPO decoder says:

Your query has found 1 match!
Here are your results:
G92 : AXLE REAR RATIO, PERFORMANCE

 

Ya, I looked at the tech data on the 91 LB9 with the G92, different gears and more HP.

 

What I meant was...G92 is INCLUDED with 1LE, but having G92 does not mean you have a 1LE...If you ordered teh G92 Performance Package, then deleted teh Air Conditioning, the 1LE package is automatically selected...

On my window sticker, it lists this:

Performance Enhancement Group 444.00
Consists of:
Power Brakes, Disc frt & RR
Engine Oil Cooler
Dual Converter Exhaust
Performance Axle Ratio(3.42 on my 1LE)

 

g92 was only a performance rear end combo, what the combo is, i dont know, but it usualy went with the g80 rpo for posi. i think that there were only 2 305's offered. the LB9 which was the TPI
or the LO3 which was TBI, and then there was L98 for the 350 tpi.
I know in 88 or 89 they went to a better cam for the LB9and offered the n10 option, dual cats. along with the 1le, g92, and in 91-92 the B4C police option. also if you got the 91-92 lb9 with a 5 speed, those cars (stock for stock) could almost runs with the 350's. Of coarse, dont quote me on this

 

Personally, I think the 91-92 LB9's with 5 speed and the G92 package would be quicker than the 91-92 L98's with the G92, only because the manual is lighter and there is less drivetrain loss.

Are there any stock 1/4 mile times and 0-60 times for these years and models?
I'd really like to know.

 

You can quote me, though...

 

G92 meant the better rear end ratio for both 5-speed TPI cars and automatic TPI cars. On 89-92 models, it also meant the upgraded exhaust with dual catalytic converters. Non G92 models were 205 HP for the 89-92 305 TPI and 230 HP for the 305 5-speed, and 245 HP for the 350 TPI automatic. The 25 HP difference between the 305's is attributed to the exhaust, and a little bit of underrating by GM. They have the same cam from 90-92 for sure, the 88-89 years I do not know for sure.
The 305 5-speed G92 and 350 automatic G92 both ran about the same 1/4 mile time, but the 305 was a couple tenths and 1 or 2 MPH slower, on average.