whats the history of the vehicle? was it from a dealership or private owner and if the latter, any idea on how many previous owners were there? did the car come with any mods done to it? from the 2nd to last and last pic, looks like the car has headers and not the stock manifolds.

 

 

Probably changed, I think 1998 had perimeter bolted valve covers..

 

the heads also could had been removed and swapped with a different set of heads and put back on opposite sides. see if there's any numbers on the ones near the firewall. will prolly have better luck looking at the heads on the driver's side.

 

Heads are the same both sides.

Looks like somebody ground off the casting #. (Pass side front, driver's side rear)

Definitely newer than 98. Been swapped, no question.

 

 

Looks like an Iron block from the picture? Maybe just dirty If so then its probably a 4.8/5.3 and someone scraped the numbers off the heads so it wouldn't be a dead giveaway

Or maybe there some ported heads and thats the way the person that ported them stamps his LS heads lol

 

Under the valve cover there should be #'s on the head.

 

Very strange and that's definitely an iron block like someone mentioned earlier.

 

 

Does a magnet stick to the block? Might have a 6.0 in there.

 

If it's an iron block, it's either a 4.8, 5.3, or 6.0. There should be an indicator on the end of the block.

 

 

THat stamp doesn't actually tell you anything. The casting number is located on the back of the block on teh drivers side, just behind the cylinder head. Just below that, inside where the bellhousing bolts up, it has a stamp indicating the displacement of the motor.

However, nothing will REALLY tell you anything unless you do some disassembly. Motor could be bored, stroked, etc. WHat did the previous owner say was in it?

 

Is it just me or is your temp sensor busted?

 

No I think you're right ... it does look kinda ... impaired. Challenged maybe even.

The block does look cast-iron. So, not a LS1. Might be a 4.8, 5.3, 6.0, or something; but not the original motor.

 

Thats always the first thing I check before buying, could be a 6.0 but like I said earlier Im almost certain someone just scraped the numbers off of some 4.8/5.3 heads so no one would be able to tell what was in it. Ive seen it MANY times were people try to pass off a 5.3 swapped car as a LS1 but never seen someone scrap the numbers off the head to cover it up.

 

Pretty hard to pass off a 5.3 iron block as an LS1 seeing as how there are NO 5.7 iron blocks from the factory. If it's iron, its either a 4.8, 5.3, or 6.0....