Cylinder head I.D.

[John #41175]

My 1965 327 c.i. engine seems to have heads from two different engines. My question is are there differences in the two that make any difference? The casting numbers are: left has GM2, 3782461, D65 and the right has GM4, 3890462, D66. If I have decoded them properly from the NCRS Spec Guide, the left is "All 327 c.i. engines", 1965 and the right is "300 and 350 hp engines" in 1967.

[John #41175]

Re: Cylinder head I.D. 1965

I forgot to put 1965 in the Subject line

[John H.]

Re: Cylinder head I.D.

John -

Both heads have similar-sized combustion chambers, but the castings are unique and were cast a year apart (the 461 in April '65 and the 462 in April '66), and originally came from different engines. Both castings were finish-machined for both small (1.94/1.50) and large (2.02/1.60) valves, depending on the final engine application.