2blu442

After seeing the strange casting code on the 1965 block TK-65 posted I looked at my 1965 stuff to find that the "A" heads appear to have had two different castings. One with the EGR humps and one without. Then I also discovered that it's not a matter of early without and later castings with, as the non EGR casting has a julian date code of 165 and the one with them 131. In addition it appears that there's no hump inside the port on the one with the external casting for it. So.... maybe 1965 was a year for Oldsmobile to experment with the "new" engine platform? And did any of the 1965 models have the A.I.R. setups on them, or was this in preperation for the 1966 model year of California Emissions cars?

And I just realized looking at the photos the EGR one has a letter A after the 6 digit casting numer!

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J-(Chicago)

I just noticed that same thing for the first time last year.

F-85 on here had 2 pairs of A heads for sale that I looked at. Some with bumps, and some without.

rocketraider

You've figured it out yourself, John. CA emissions (smog pump) heads had that AIR boss cast in.

And since Olds used the smog pump only 2 years and only in California-destined cars, I never understood why all the later heads had the bosses and the bumps. Guess they were trying to "be prepared".

aliensatemybuick

I was not aware of CA emissions / AIR cars in '65, but even if they were available, and that explains the AIR bumps castings on some heads, wouldn't they be drilled out then?! Has anyone EVER seen a set of drilled out AIR bump '65 heads?

joe_padavano

Just to clarify, they aren't EGR bumps, they're A.I.R. bumps, and the Calif requirement was 1966-67, not 65. These are definitely unusual heads.

rocketraider

To hazard a guess, they may have been research heads that they were playing around with anticipating the 1966 AIR requirements. Though when they changed head designs the new casting usually got a different number/letter ID.

507OLDS

The A-heads without the bumps are the earlier castings.I had a set of those in the late 90's.That is also a cheap upgrade for the stocker guys.I also had a set of #3 heads the same way.