I just realized this after reading the post about p/v clearances....when I did the head swap I wasn't thinking much about it at the time due to the 1500 other things I was thinking about but I KNOW they were flat (I had to clean coolant and junk out of 8 cylinders...I ought to remember)

I was under the impression that the LQ4 had dished pistons and the LQ9 had flat-tops, with the flat-tops and 66.67cc chambers my compression is gonna be ALOT higher than the 10.1:1 that I figured on....closer to 10.8:1

is it possible that the 99-00 6.0's with the Iron heads had flat-tops ???.....I'm pretty sure just by eyeballing it that the Iron head chamber is bigger than 71cc, is it possible that GM went with flat-tops to bring the compression in line due to larger chambers ??

 

Gonzo had a 99-00 6L. Lets see what he says.

I guess you could have a 4.8 with iron heads.

 

I bought Gonzo's iron heads from him.....I went out and compared them last night to the ones I took off and they are definitely the same head

 

before this turns ugly....HOW MUCH of a dish should they have ???....if it's nothing more than a concave surface across the whole piston it COULD look and feel flat, but if they are like ALL other dished pistons and it has a rim around the outside and a VERY pronounced dish then I DEFINITELY don't have dished pistons !!

 

I believe the 6.0s all have the same head chamber configuration also.Its been several years since mine was down,dont remember mine being any different than my buddys 02 LQ4,If i was to guess,I think there was a rim about 1/4 around,slight dish with valve reliefs.

Have Greggo post a pic.

 

My pistons are flat.

 

OK....now there's two of us......I feel a little better

Gonzo...that piston configuration you described is what I WAS expecting to see (same design as EVERY other dished piston), but mine are TOTALLY FLAT

 

Same hear

 

Mine very well could be and problably is,i just cant remember.I am still under the impression all Lq4 pistons are the same.

 

I had my heads off a couple of weeks ago, definatly flat.