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SuperNovaSS
10-03-2009, 02:16 AM
I have 2 3964291 rectangular port heads. Both are cast D 23 70. The strange thing is the heads have "HI PERF" cast into them. This may be common but I have never noticed it before. Here is a picture of what I'm talking about:

http://i179.photobucket.com/albums/w301/super-novass/291Heads003Small.jpg


Jason http://www.yenko.net/ubbthreads/images/graemlins/beers.gif
SuperNovaSS
10-03-2009, 02:20 AM
http://i179.photobucket.com/albums/w301/super-novass/291Heads002Small.jpg

http://i179.photobucket.com/albums/w301/super-novass/291Heads004Small.jpg
John Brown
10-03-2009, 06:13 AM
Make sure they are both machined for the same style spark plug too.
Rixls6
10-03-2009, 02:41 PM
2 different styles of "HI PERF" being cast the same day is interesting.
Like John Brown said, check to see if they both take the same style spark plug.
JRSully
10-03-2009, 04:58 PM
To my understanding, the Tonawanda foundry had multiple molds for the same head, with some having slight cosmetic differences from one to the next. I am sure some of the site members here can give a clearer answer on the subject
Chevy454
10-03-2009, 05:29 PM
[ QUOTE ]
Make sure they are both machined for the same style spark plug too.

[/ QUOTE ]
Also, make sure they're cast for the same size valve seat...
SuperNovaSS
10-04-2009, 03:33 AM
They both use the same style park plugs and look to have the same size valve seats. I guess there were just different molds. Learn something everyday.


Jason
JohnZ
10-10-2009, 03:55 AM
To be more precise, high-volume castings had multiple PATTERNS (made of cast iron or stainless steel); when sand was packed around the pattern, it created a sand mold. The sand mold was opened, the pattern was removed, and the mold was closed. Iron was poured in the sand mold, and the sand disintegrated on the "shake-out" table after cooling, when the raw casting was removed.

Each pattern was numbered and carried the casting number, casting date and hour clock; that appeared on each casting, and enabled internal traceability in the foundry back to the pattern in the event of a problem with a casting.

The casting number, casting date, and pattern number were individual brass characters soldered to a brass plate that was pinned or screwed to a recess in the pattern; the date tag was changed every day, and the clock tag was changed every hour. Photo attached of tags from the Saginaw Foundry.

http://www.yenko.net/ubbthreads/images/graemlins/beers.gif
Chevy454
10-10-2009, 05:06 AM
Cool stuff, John...