I need some help quick on making a decision on whether I should buy this car, so any help would be appreciated, I have to make my decision soon, or someone else will end up buying with my luck.

I am checking out its 91 Z28, had an accident on the driver side door so it was painted and paint looks really nice. It has red leather interior, really clean, perfect seats and carpet except for the driver seat, which isn't a problem for me.

However, the owner says even though the vin number and window sticker says it has a 5.0 TPI, it really has a 5.7 because the initial owner did some special order for it, and he showed me a yellow slip stating he got a 5.7 liter. He also said that when he was getting a starter for it, he had problems because it was really a 5.7 not 5.0.

Visually, is there anyway I can tell if it is 5.7 or 5.0? Location of dipstick or anything like that? I really want this car, its almost perfect, except for this one problem.

Also, the speedo has a max speed of 110, isn't that weird? My 86 z28 even had a 140 mph speedo, how would a 91 z28 have a 110 speedo???

Thanks for all your help!

Suke

 

Sorry I can't give you too much help but on the block there is an ID number that will identify the size of the block. I am thinking its a little tab just in front of the passenger side cylinder head that might say something like 5.0 or 5.7 but it may just have an id number which you would have to look up.

Im not sure that this is where the number is but I know that its a certain way to check the block once you find it

If it helps I can tell you that all 5.7s came with 4 wheel disc brakes and a higher tach and speedometer than the 5.0L TPI with automatic transmission.

 

Yea that does help, thanks for the reply.

I have also found out that 350s came with square shifter ***** while 305s had round ones... this one had a round one.

And, it was missing the RPO list sticker! Everything says its not a 5.7, yet he says it is and shows me what he considers "proof." The guy doesnt know much about cars, he was selling it for his sister or something...

Is it possible that the original owner could have special ordered GM to put in a 5.7 for him, even though everything says its a 5.0?

 

It could always be a transplanted 350, so be carefull. I know my 350 had the squad shifter when it was still an automatic.

 

I have also found out that 350s came with square shifter ***** while 305s had round ones... this one had a round one.

Wrong. I'm familiar with the database where this information came from and it is incorrect. Except the Berlinetta, all 1986 and prior years' automatic transmissions were round. All 1987 and newer were all square. You are talking about an automatic, aren't you? Because all 5-speed ***** are round!!


And, it was missing the RPO list sticker!

Although not always the case, a missing RPO sticker (SPID), is an indication that some sort of fraud has occurred. Be very wary of a car with a missing SPID.


Everything says its not a 5.7, yet he says it is and shows me what he considers "proof."

Look for the "pad" shown in the red ellipse in the pic below. (This is my 305.) On this pad, there should be stampings. If there is, post what you've found and we'll decode it. It is possible the pad is clean too. If it is, it won't prove anything.

I also have another pic to follow.


Is it possible that the original owner could have special ordered GM to put in a 5.7 for him, even though everything says its a 5.0?

If it's a factory 350, the 8th digit of the VIN would be an "8", no exceptions. Of course, that doesn't mean someone (including a GM dealership) didn't swap engines.... Is the "proof" you have a receipt of some sort? Who is it from?

 

If you can see the back of the engine block on the driver's side, look for a casting number (see pic). Notice where it says "5.0L"???

Willie

 

Yes Willie I see, that information was quite helpful. I'm going to be a bit more cautious since it doesn't have the RPO sticker.

I may not be remembering correctly, but I am sure the 91 Z28 I tested today had a round shifter **** and it was an automatic. I remember this because I was expecting a square one and was surprised to feel a round one.

I will however check again when I go to see the car again.

The reciept he offered as proof was one that the original owner got from the dealer, but I didn't inspect it that well, which I will make sure I do next time I go check it out.

What do you think about the 110 mph speedo? It's sort of odd isnt it? I read only convertibles came with that speedo.

Also, do you have any recommendations on how I can look at the block on the car? Is it easily accessible without removing parts or putting it on a lift? Thanks.

 

From everything you've stated, I have a gut feeling about this car -- that maybe it was pieced together. When you go check it out again, look for paper VIN stickers on both doors, hood, and under the decklid. Make sure they match the VIN tag in the windshield. There are also paper VIN stickers on both fenders, both rear quarter panels, front and rear end framework too, but are more difficult to see. If I were considering buying this car, I'd go over all this and more with a very fine-toothed comb.

Willie

 

The doors didn't have any information on them, they were just blank, only painted, I was looking there for the RPO sticker after I couldn't find it in the car. I will check for other vin stickers that you mentioned. Thanks for the help, I think I will be able to determine what is up with this car when I go to check it out, and if its a 350, I will probably give cash and drive it home.

 

I would beware of missing VIN information. This sounds like a sham to me. But for the right price a 305 car is still a good deal.

 

When the seller says its a 350 and the Vin indicates a 305 walk away. Unless the seller has complete paperwork on a engine swap, such as engine invoice, shop invoice & etc. Most sellers are honest except when it comes to the motor, then all 305's are by magic 350's. I swapped in a 350 and I have a 1" thick folder with the paperwork to prove it.

 

Hmm, the only invoice that he had a was a tiny yellow reciept saying 5.7 engine and oil coolers, so right now I'm pretty sure its going to be a 5.0. I also find it hard to believe the dealer would change it, because that would void the warranty or it wouldn't be under warranty or something.


But, since its so beautiful!!! I'm going to offer 3k for it. I really want a black 91 or 92 z28, and this is the first time I've seen one for sale in my area (NJ).

 

As long as you are aware of it not being a 350, go for it by all means.

 

Before this one gets closed also, I just wanted to say thanks for the help, I am looking at the car tomorrow to see if its a 350 and giving an offer. Wish me luck... thanks again.

 

Just look on the back of the block, on the drivers side. It will say either "5.0LG" or "5.7LG". That is the dinifinate answer.

 

So here is what happened... I went to check out the car but it wouldn't even start. It was probably the starter or starter relay or maybe something electrical. I looked for the engine code, behind the block on the driver's side. I couldn't see or feel anything.

I think it was too far down for me to reach with my fingers to feel, and I just don't see how it can be accessed. I was concentrating in the area under the windshield wiper motor, behind the driver side valve covers area.

The seller said he would contact me when it was repaired, so I may have another chance to see if its a 5.7 or 5.0, any other tips anyone would like to provide? I used a flash light and had a small mirror and even an old toothbrush ready to clean it, but I just never found the numbers.

 

With a flashlight and a mirror, you should be able to see it. Look between the dirver's side head and the transmission, by one of the trans bolts.

 

The reason you might not have felt the numbers either is it could be a older block that didn't have the 5.0L or the 5.7L.