C2 Cyl HeadCasting date discrepancy

[William V.]

Cyl HeadCasting date discrepancy

I have questions about a 1966 427/425. The number information is as Follows:

Production number 21439 & vehicle assy date around May 11, 1966
Block cast number 3869942 & cast date D1 6 (Apr 1, 1966) there is a digit space between the 1&6

Engine assy date/code T0504IP. Tonawanda plant, May 04 425HP.

Right cyl head E276 May 27 1966???
Left cyl head F226 June 22 1966???

My problem is the cylinder casting dates. Am I correct in my casting date analysis and in concluding the heads were changed after the car was shipped? Probably warrantee work.

Thanks

BV

[William O.]

Re: C2 Cyl HeadCasting date discrepancy

Also you check the casting numbers of the heads.
Should be 3873858 .

[William V.]

Re: C2 Cyl HeadCasting date discrepancy

sorry, on my post, I leftout the casting number on both heads. The number is 3873858.

[Mark #28455]

more likely not original heads

They're not likely to be the original heads, but who cares! NCRS doesn't judge the casting numbers or dates on heads. Externally, they are identical to the original heads so you're set!

I would doubt they were from warranty work however as I wonder what sort of failure would take out both heads but leave the block intact. You would think the dealership would have just requested a complete engine to replace such a catastrophic failure.

Although not likely, it could have happened. I would more likely bet somebody hot-rodded the engine and swapped the heads. Later on, when they decided "original is better" somebody tracked down a set of correct casting but incorrect date heads and put them on. But again, it really doesn't matter as nobody can see the dates on an assembled engine.
Mark

[John H.]

Re: C2 Cyl HeadCasting date discrepancy

Bill -

Yes, the heads have been replaced.