Chevy OE cranks, cyl. heads.

[Billy Nees]

I have always been told that an X was put into the core box when it was worn out.
Now, that could make sense or maybe there were some Racer types loose in the foundry who had found some really good core boxes and made sure that special projects used these pieces.

[bubski]

This could be the smoking gun as to the great 283 intake travesty !! But the 'damage is already done ' !!! OMG the 283s are taking over the eliminator !!!

[Greenlight]

Some additional links that may not be as useful, but refer to casting marks such as "CFD" (Central Foundry Division) and engine markings "F" (Flint) and "T" Tonawanda being used to identify origin.


https://www.mortec.com/location.htm
https://www.mortec.com/locatpg2.htm

http://hotrod.gregwapling.com/chevrolet/mckinnon.html

https://news.pickuptrucks.com/2011/0...g-center-.html

[Ed Wright]

Originally Posted by bubski

This could be the smoking gun as to the great 283 intake travesty !! But the 'damage is already done ' !!! OMG the 283s are taking over the eliminator !!!

I had one pair, and saw one other 520X. My '56 was gone by then.
Never found any X castings for my LT1. LOL

[Adger Smith]

Billy, My buddies at Brodix tell me that as their Core boxes wear the port is cast smaller.
I was questioning them one day about their advertisement for port size and flow. I told them that what I buy never matches the advertised size and flow.
Dave Roder told me it was because all the ads are done off the first production run and as they pour/cast more heads the ports get smaller.
I'm no foundry expert so I just shut up and accepted the explanation.
Probably what they wanted me to do, LoL.
I would bet that the GM X means the mold/core box was modified. If the X was for worn out why would they be using them? No doubt the X castings I've seen always seem to have more intake volume.

[Dwight Southerland]

Originally Posted by Billy Nees

I have always been told that an X was put into the core box when it was worn out.
Now, that could make sense or maybe there were some Racer types loose in the foundry who had found some really good core boxes and made sure that special projects used these pieces.

Has anyone ever seen a '61 or '62 date code 461 casting that was NOT a 461X? I haven't and I have seen 20 or 30 of them in junk yards.

[Greenlight]

Dwight, according to the source below and other sources the 461 and 461X casting numbers date back to 1961 (first 327 engines).

http://www.corvetteactioncenter.com/...gines-286.html

http://www.chevytech.com/3c3782461.html

[Adger Smith]

Interesting,
No 22542525 heads on the list.
Olds Nascar head/