I am a new user, and I know this question has been asked 100 times already, but I cannot find it posted.

Would someone point me where to look?

I am going to look at a supposedly L98 1992 Z28 this weekend (8th VIN digit is an 8). I have seen photographs of the engine, and it is obviously a TPI engine. However, just because it left GM as a 5.7 does not mean it is still a 5.7 11 years later.

I would really like to find a way to identify whether it is a 5.0 or a 5.7 engine. It is an automatic, so no indication there.

Also, the engine is still in the car so visibility is limited.

I know this must be posted somewhere on this site, but I have looked for an hour and have not found it yet.

Bill S.

 

I'm not number one on this subject....but...I think the actual engine looks the same from appearence. (sorry if I'm wrong everyone) Me....I can tell the difference from a 5.0 and a 5.7 like night and day if it has an aftermarket exhaust system. If anyone has any info.....as far as the appearence goes....please post...cause I'd like to know too...

 

They look the same externally. The easiest way is to try and find the casting plate on the driver's side against the firewall. With these late model blocks they actually cast in the 5.0L or 5.7L If it isnt there you can always run the block casting number on www.mortec.com

 

iroc22,

Thanks for the information.

Just to clarify, I assume the plate is on the block itself and not the heads or intake. Also assume it is above the transmission.

Should I be able to see it from above, or is it attached to the back of the engine so that I need a mirror?

Just saw on this site that all L98, 1LE, and B4C cars have an oil cooler. Since 1LE and B4C are pretty rare, I was wondering about using this as a suggestion (but not proof) that the enginer is correct. What do you think?

Sorry for the additional questions, I am just getting excited about possibly getting another "fun" car.

Bill S.

 

Oops, just went to the link and got the answers about the location. Sorry.

Bill S

 

All G92 cars got the oil cooler.

 

I judge them from the air intake (which I thought differed) and the speedo which is sometimes 140 MPH for the full 350 small block.
Mine also had dual enhaust but can't say for sure that's 5.7 only but was one thing that impressed me when buying my ride.
Mine's an 89 so I'm not as up to speed on the later cars.

Another Bill S. ...just great!
Bill S.

 

The intake's were the same on the 305 and 350. You could get the 140mph speedo with either engine; it was part of the G92 package. The dual cat package could be had on both engines once again as it was part of the G92 package (RPO N10).

 

Check the Vin number at the base of the windshield. the eigth letter/diget give you the engine. LB9 (305TPI) is "F" L98 (350TPI)is "8". If the reply is the engine was swapped ask for paperwork or walk away.

 

I was thinking the route of the lead in hose to the plenum to be specific. As the package you refer to, wasn't the default to have the 140 on the biggest engine unless it was an order for the smaller one? I'm just trying to get a fix on this and not mislead anyone. Thanks
Bill

 

Well the routing may be different on the birds but on the Camaros (which he is talking about) is the same for both engines.

Yeah I'm fairly certain that all 350's got the 140mph speedo, while the 305 had to have G92 specified to receive the bigger speedo.

 

Speedos can be swapped out tho. I'm curious to the same thing(how to tell a 350). I have a 350 in my 86 T/A which originally came w/a 305(both tpi). I know it's a 350 because I put it in there! My 89 Formula 350 was the donor car. I never plan on selling this car--but in the event of something happening--whoever runs my vin will come back w/a 305. Since it's an 89 motor(has the oil cooler on it--but lines aren't connected)will it have that pad w/the 5.7 on the pass side rear of the block? I have the dual cats to put on it, also has the dual fans and the 140 speedo w/3.27 gears(was a G92 car)--so all the 350 clues are there--except for the vin.

 

Yes it will have that plate.

 

Yes, it's on the block. You won't be able to get the correct angle to see it. Bring a small mirror, and a rag and some brake clean to wipe any dirt, grease, or oil that may be covering it up.

It's on the driver side, not the passenger side. See attached picture.

 

cdartz,

Thanks for the photograph. It really clears up where I should be looking.

Bill

 

That's an older block in the pic, but it's still the same. The 5.0L or 5.7L is under the casting #, closest to the firewall.

 

No problem Bill. It wasn't anything but a quick 2 minute photoshop job. I'm glad to help.

Chris Artz

 

What all came with G92? I have 145MPH speedo and I have the LB9 engine. Not the L98. I checked the RPO decoder and it listed G92 as rear axle ratio performance stuff. Says nothing about speedo.

My car has 2.73's or 2.77. I only know from the 70 mile an hour trick in drive.

 

Look for the VIN on the block. Stamped on a pad forward of the passenger side head. It won't be the complete vin, the 1G1FP part is deleted. You will have to probably move some stuff out of the way, but this is the most accurate way to make sure it is the original engine. While you are looking for the VIN, there is another alphanumeric code there too. Note that and reference it in the white book or post it and someone here could figure it out. If I find a pic of mine, I will post it.
Good Luck.

 

Here is what I can do for you. It is not the best pic, but it is what I have available right now.

 

Good info. I have been wondering if my car had the original engine in it or not. It pulls to hard according to the butt dyno to be a stock 305. We shall soon find out.

 

Well G92 usually consisted of a package of stuff. When G92 was specified on an auto LB9's (up until 88 or 89) it included a disc brake rear end with 3.23 gears, oil cooler, 145mph speedo and limited slip unit. The only difference between the manual and auto LB9 before 89 IIRC was the higher geared rear end (3.45) in the manual cars. Even with G92 I'm pretty sure all the auto LB9's still were rated at 190 though and the manuals 220.

 

Isn't the redline on the L98 5500 and the LB9 5000? that would be an easy way to tell. but if it isnt the original engine, you can always check the block.

 

on my car theres still the sticker on the inside of the hood, by the passenger side that says what engine it is. but in most cases u hardly see those on a car.

 

Yeah that would work since the manual LB9's had the 5500 redline while the autos had the 5000 in 92.

 

The early G92 cars only had the performance rear upgrade with no other options... after 1989, G92 became a full performance package consisting of multiple performance upgrades. Also, the G92 "5-speed" cars had a bigger/more aggressive cam from the factory. Before the G92 option became a full performance package all 5-speed cars came with a more aggressive cam design versus the automatic cars. In 1988 there was two different G92 options... one with A/C and one without A/C, if you ordered G92 without A/C it triggered the 1LE "road racing" option, which was GM's way of getting factory performance parts on the F-Bodies, to compete with the Saleen Mustangs in Showroom Stock road racing, and it worked very well as GM took the manufacturers title from the Saleen Mustang the following year, as the Saleen Mustangs were dominating up to that point. I have quite a bit of detailed information on these options on one of my websites, www.StreetShowDriftDrags.com as well as my other www.Mustang-Town.com website... also have some videos on YouTube of my G92 optioned IROC-Z

 

Wow, search must be working well for you to dig up a thread from 2003...