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Author Topic:   461 head question
posted October 03, 2003 07:45 PM
I got a set of 461's that have the following markings:

On the top:
GM 3 (the other has a 4)

On the bottoms
461 1

My question - Are these the famous "X" heads? I'm porting them to the max and they are turning out freaking beautiful but just wondering if they are in fact "X" heads? Any help me out here?

posted October 03, 2003 08:13 PM
41 years by my math

posted October 04, 2003 09:10 AM
I like autoshops math a whooooole lot better.
Woo Hoo I'm 17 again!!!

posted October 04, 2003 09:29 AM
We've at least figured out that I have a set of heads the same age as me! I was under the impression that the "X" would be with the casting number too but I've done some port work on several sets of 462's, 441's & 882's and these intake ports just seemed so much better than all of those from the start. This, plus the "X" on the bottom got me curious. My goal is to make these produce numbers close to the aftermarket heads (for my version of a poor boy big show motor!). I'm porting these as recommended in David Visar's book on modifing Chevy heads. Anybody got a clue what kind of HP these puppies are capable of producing if I get this port work done correctly? I've been putting in the time I just hope I get the desired results.

rico 08
posted October 04, 2003 11:12 AM
Probably close to 450 horses if you do a excellent job,here's a link to an engine combo comparison webpage that really shows how much better aftermarket heads and high swirl gm heads are than the older stuff.HTTP://

[This message has been edited by rico 08 (edited October 04, 2003).]

posted October 04, 2003 12:04 PM
Originally posted by 15a:
The 461X heads I have seen have the X in the casting number following the "461".

I've owned a few sets of 461x heads and none have ever had the "X" in the casting number. The "X" is always on the bottom side of the head. The only way to tell on the top side of the head is by the date code. 461x heads were cast sometime in 1961 up til June of 1963. Starting in July of 1963 and after, no 461 heads were "X" heads.

posted October 07, 2003 08:01 PM
Cool! Sounds like I got me a set of "X" heads. Thanks guys.

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