Originally Posted by nervous71 (Post 4913457)

I've been researching all my casting numbers, but I have something I hope an avid expert can help with.

My heads have cast numbers of 3998991, roughly '68 to '76ish 350 1.72/1.50 valves. The thing I need help with is, and I don't know if it matters, one head has a stamp date of A254, the other, a stamp of P104.

As far as my research has gone, I know A= January, 25= day of month, and 4= year? '64?, '74? These are supposed to be the original heads, it was my dad’s truck bought off the show room floor in 1971.
And the P, what’s that mean?

Appreciate some clarification.

Originally Posted by nervous71 (Post 4913770)

Yes, having the 350 short block rebuilt. The question was the P104 cast in one of the heads, all my research shows A through M was used for casting dates, one of mine has a "P".

Originally Posted by Captainfab (Post 4914316)

Are you sure it isn't a 'D' ? Sometimes the casting is a little rough and hard to deciefer the numbers and letters

Originally Posted by Mxracer202 (Post 4282944)

can't believe no one has added this one yet by far probably the easiest, just type it in and it will find it.

Inline 6
http://www.adchevy.com/tools/castinglookup/