Can someone refresh me. I have a 67 cutlass supreme a buyer wants to be sure I have a 330 hi comp. engine. What is the casting # sequance to help me read the cyl. head numbers?

 

Any '67 330 should have a "4" huge ID on the corner at the #1 or #8 spark plug area.

The W....G or similar STAMP in the front end of the RH head will tell if it was originally a 4-bbl, 2-bbl, High Compression or not, etc.

Of course any engine can have #4 heads.
If you want to be more certain that it's a 330, look at the BLOCK casting ID aft of water pump, fwd of intake, atop the timing cover. The ubiquitous 350 is 395558-2 with a much larger "2". The 330's are main ID 1 or 3, and I forget their 6-digit casting numbers.

How the hell they got a "3" 330 before a "2" 350 is a mystery. I will postulate that they had the 350 almost ready to go earlier but then plans changed, and since the ID "2" was already taken, the last 330 had to be called "3".

 

A 67 330 should have #4 heads, it will be cast to the left of number 1 plug hole.

 

Did you try a Google search such as
"1967 olds 330 high compression head stamp"

e.g.
https://classicoldsmobile.com/forums...ification.html

"1964 ~1967 code is stamped on the right head this code consists of a letter 330 v8=T than a production sequence number followed by a suffix code letter ( L=low compression E=2-bbl export G=high compression H=4-bbl quoted fro 442.com"

Then there's

It's in the Chassis Service Manual on Wild About Cars. Section 0...

Wild About Cars. http://wildaboutcars.com. An information supersource, especially Oldsmobile. More Olds content than anywhere else on the internet and continuing to grow.

also [with photos and everything!]

https://classicoldsmobile.com/forums...67-engine.html

"This will help. Stamp on the right cylinder head. Should start with a "W" and end with either a "L", no letter or a "G". "L"-260hp, 310hp, 320hp for "G". Export engines have different code."