Strange Casting Number

[Andrew J.]

I have an early 1967 Corvette with a 3869942 block (427) that has the casting number ground off and restamped 3904351. During engine over haul I found 942 cast into the block near the camshaft journals on the inside of both front and back bulk heads. Colvins "Chevrolet by the Numbers" indicates that this is something that Chevy did in late 66 and early 67. However, the '67 judging guide makes no mention of a hand stamped 351 casting number. My question: is this block recognized by NCRS as something Chevy did, or do I have a real oddball?

It doesn't make sense to me that someone would think they would have something to gain by grinding the casting number off a 942 and restamping as 351. For what I know, the 942 required a groove in the rear camshaft journal to allow oil to flow to the lifters. The 351 changed that and put the groove in the camshaft hole, below the pressed in bearing. So I assume Chevy took some 942 castings and machined them as 351's, and restamped accordingly - just my guess.

[Joe L.]

Re: Strange Casting Number

I have an early 1967 Corvette with a 3869942 block (427) that has the casting number ground off and restamped 3904351. During engine over haul I found 942 cast into the block near the camshaft journals on the inside of both front and back bulk heads. Colvins "Chevrolet by the Numbers" indicates that this is something that Chevy did in late 66 and early 67. However, the '67 judging guide makes no mention of a hand stamped 351 casting number. My question: is this block recognized by NCRS as something Chevy did, or do I have a real oddball?

It doesn't make sense to me that someone would think they would have something to gain by grinding the casting number off a 942 and restamping as 351. For what I know, the 942 required a groove in the rear camshaft journal to allow oil to flow to the lifters. The 351 changed that and put the groove in the camshaft hole, below the pressed in bearing. So I assume Chevy took some 942 castings and machined them as 351's, and restamped accordingly - just my guess.

Andrew-----


What you surmise is exactly what they did. They used the original '942' casting and THROUGH A MACHINING OPERATION converted it to a FUNCTIONAL EQUIVALENT OF A 3904351. So, to recognize that conversion and properly ID the block for internal purposes, they ground off the original casting number and stamped-in the new one.

Are these accepted for judging? I don't know, but I would expect they are. It's a pretty well known and verified sort of thing.

[Joel A.]

Re: Strange Casting Number

Very interesting!! It just goes to show that the manufacturers will do whatever needs to be done to get it out the door. Why should they worry about future restorers?
Good info here!