1966 427 Head gaskets

[John P.]

Hello, I am doing a valve job on a friends 1966 427/425 corvette. I have always used Fel Pro high performance head gaskets and have a question regarding their 1037 head gasket. Is there any advantage to drilling the additional cooling holes in the block deck to use these gaskets and are there any additional cooling system modifications required? Does this modification have any benefit to the cooling efficiency, or a waste of time? This engine will be used mainly for street and occasional race use. Would the 1027 gasket be better for this application even though they are recommended for aluminum cylinder heads. Thank you in advance for any and all advice, John

[Joe L.]

Re: 1966 427 Head gaskets

Hello, I am doing a valve job on a friends 1966 427/425 corvette. I have always used Fel Pro high performance head gaskets and have a question regarding their 1037 head gasket. Is there any advantage to drilling the additional cooling holes in the block deck to use these gaskets and are there any additional cooling system modifications required? Does this modification have any benefit to the cooling efficiency, or a waste of time? This engine will be used mainly for street and occasional race use. Would the 1027 gasket be better for this application even though they are recommended for aluminum cylinder heads. Thank you in advance for any and all advice, John

John------


If the Fel-Pro 1037 gasket is used with a Mark IV passenger car block (which includes Corvette blocks), the three additional cooling holes MUST be drilled in the block. Basically, the 1037 is a Gen V and VI big block gasket which can be used on most Mark IV engines IF the holes are added. Why go through this? I do not recommend the use of the 1037 gaskets with any Corvette block.

Instead, use the Fel-Pro 1017-1. This gasket is compatible with BOTH cast iron and aluminum heads and is designed for use on Mark IV big blocks. This gasket has a somewhat larger bore size and is about 0.002" thicker than the 1037 which results in about a 1 cc increase in volume. Nevertheless, in my opinion it's preferable to drilling the extra holes.