Hi,
I came across a set of Olds heads for 20$, needless to say I snapped them up. I was told they were from a '68 350. How can I ID them to be sure? My plan is to have them rebuilt and then replace the tired ones on my 68 Cutlass ( also will rebuild the short block).
In the same vien, I was reading my Motors Manual and see that 68 350 have a couple different compression ratios listed. Are the differences soley related to the combustion chamber size? and again, is there a fairly simple way to ID which is which?
Any minor performance tips for these heads would be appreciated too!
Thanks!!!

 

Carnac the Magnificent says,

"What # or lettters do they have on them. Post and someone will shed some light on the subject."

 

It is very easy, they will have a large number on the corner, in this case if it is a 68 head it should be a "5" Cylinder head volumes were the same, compression ratios were changed by using a different sized dish in the piston.

 

Excellent help captjim, thanks! These have a "8" so I suspect they are from a 73-76 ( found a cool website to help in ID'ing)and not a 68. I seethe ones in my car now are "5", is there a way to determine the compression ratio without removing the heads to see the pistons?
Thanks again.

 

You can do more that "suspect". You can be 100% certain.

No, unless you have xray vision or a borescope to look in the spark plug hole at the size of the dish.

 

To add to Joe's post, the factors determining Cr are the piston dish, depth in the hole, gasket bore and thickness, and cylinder head volume. There is a tiny amount between the piston and the top ring. So, there are several variables. If the engine has never been apart, the Cr should be in the low-mid 8.xx to 1 neighborhood. But, that is just an estimate. Read this if you care to,
http://www.oldspower.com/vb/showthread.php?t=36717

EDIT Obviously, bore and stroke are primary factors, too. In the case of an Olds 350 it is 4.057 x 3.385.