I know my heads were milled before I got them, but I have no idea how much.

Is there a way that I can find out?

They are L92's.

 

did you buy them used? If so, other than ask the original owner, I'd have to say CC the heads would be the only way i can think of.

 

I think the only way at this point to determine that would be to cc the combustion chambers. Someone else correct me if I'm wrong but I believe the L92's are supposed to be 70 cc combustion chambers + or - 1 cc. Once you get the size of the combustion chamber you can get a rough idea of what was milled. I just had .025 taken off my L92's and they were 65 cc's after being milled.

 

I bought them used, and the previous owner told me they were milled .020.

However the shop that built the shortblock said they were 64cc.

I know know who is right? Dont get me wrong, the 64cc would bump me in compression which would be great.

I'm trying to determine my CR, and also check the valvetrain geometry.

 

unmilled is 68.4cc +-1cc, this is per the blueprints. Mine were at 68cc stock, had .030 taken off mine and I ended up at 62cc. I did some combustion chamber smoothing as well.

 

So based on that it is possible to shave them .020 AND 64cc chambers both?

 

I have heard various ballpark figures for how many cc's the combustion chamber is reduced. I have seen .005-.007, for the sake of discussion, lets say .005 = 1cc, if they milled .020 off your heads and you started with 68cc chambers than you do have 64cc now.
The only correct way would be to check them now to see for sure.

 

Interesting, so its possible that both the shop and the seller were correct.

t/y

 

I had mine cut .030 and they ended up at 64cc.

 

The L92 heads are based on the same skeletal dimensions as the standard LS1&2 castings. The overall height of the heads measure 4.750" +or- .002". You can measure with a pair of calipers from the deck surface to the valve cover rail. Any less than 4.748" should be considered a milled amount.

Good luck.

Richard

 

Thanx for the data and tolerance. This gets saved to my hard drive !!