Machined vs NON-machined double humb symbol on 461 heads

[Tom P.]

It's my understanding that the double hump symbols on Flint heads are (or should be) machined flat and the symbols on Tonawanda heads are not machined. Is that correct?
Well, I have a pair of Dec 64 Flint 461 heads (cast date ends in 4 instead of 64) and the symbols are rough cast instead of machined flat. Is this possible?

[Mike M.]

Re: Machined vs NON-machined double humb symbol on 461 heads

never seen flint un-machined but anything possible. mike

[Jack H.]

Re: Machined vs NON-machined double humb symbol on 461 heads

Follow the drift of Mike's reply...

Just about any system made by man has exceptions, escapes, and errors. So, while it may be 'possible' for a set of Flint made heads to have non-milled end marks, what good does that possibility do?

We judge based on 'typical' factory production norms. We handle 'non-typical' (exception to the rule) situations by placing the burden of proof upon the owner.

So, if you have these critters in captivity, the next question is what do you do with them? Expect most savvy judges to assess an originality deduction for their atypical Configuration...

[Tom P.]

Re: Machined vs NON-machined double humb symbol on 461 heads

I've had these heads for MANY, MANY years, and just never had a reason to look at the ends of the heads. I was pulling a bunch of stuff out of the cabinets the other day looking for a generator (never found it ), and in the process of pulling stuff out, it just caught my eye that these heads were Flint heads (just a 4 for the year), but the symbols were NOT machined. So, I thought I'd ask is anyone had ever seen this.

[Cecil L.]

Re: Machined vs NON-machined double humb symbol on 461 heads

Tom,
I have a pair of 462 heads with single digit casting year and unmachined ends. I originally thought they were Flint untill I looked again and found a T cast between the spring seats. One is dated H-13-6 and the other is K-14-6 and no evidence of grinding...not enough space to allow a second year caharacter. One also has a Z cast near the spring seat on one end. One has a 25 cast below the first spark plug hole and the other has a 16 cast there. Never noticed this before.

[Kirk M.]

Re: Machined vs NON-machined double humb symbol on 461 heads

I was told machined = corvette. Non-machined = passenger car.

Kirk

[Joseph T.]

Re: Machined vs NON-machined double humb symbol on 461 heads

I've had these heads for MANY, MANY years, and just never had a reason to look at the ends of the heads. I was pulling a bunch of stuff out of the cabinets the other day looking for a generator (never found it ), and in the process of pulling stuff out, it just caught my eye that these heads were Flint heads (just a 4 for the year), but the symbols were NOT machined. So, I thought I'd ask is anyone had ever seen this.

Tom

Cecil brings up a good question. Do your heads have a T casting mark?

Joe

[Mark G.]

Re: Machined vs NON-machined double humb symbol on 461 heads

Tom -

Chevrolet Saginaw Grey Iron Foundry cast the heads for Chevrolet Flint Engine Assembly. Grey Iron poured the heads on conveyor 13. I don't know the head cast line number for Tonawanda, but a "T" is a good clue. So a #13 conveyor tag and finished ends convinces me.

Mark

[John H.]

Re: Machined vs NON-machined double humb symbol on 461 heads

I was told machined = corvette. Non-machined = passenger car.

Kirk

Kirk -

The distinction is Machined = Flint, Non-machined = Tonawanda.

[Tom P.]

Re: Machined vs NON-machined double humb symbol on 461 heads

OK, following the comments above, I went out and took a second------------CLOSER--------look. Sure enough, there is a T below the cast date code. But, the T in not raised like other cast numbers. It is slightly, and faintly, a depression in the head.
Sooooooooo, now that a casting with a single digit for the year, in this case a 4 for 1964, I supposed this kind of confusses the issue of a single digit for the year of a Flint (Saginaw) casting and 2 digits for the year for a Tonawanda casting.
Oh ya, the guide plates and screw-in studs are a typical owner modification.
Comments?

[Cecil L.]

Re: Machined vs NON-machined double humb symbol on 461 heads

Tom,
Check the first spark plug holes for a number cast there as shown below. This head has both the cast T and the stamped T as you found on yours. The other head has the same except it also has a Z (or maybe it's an N for nodular) cast near the outer right spring seat.
So, at least on heads, single digit year as an indicator for Saginaw castings has some exceptions. Kinda like the big blocks.

[Joe C.]

Re: Machined vs NON-machined double humb symbol on 461 heads

OK, following the comments above, I went out and took a second------------CLOSER--------look. Sure enough, there is a T below the cast date code. But, the T in not raised like other cast numbers. It is slightly, and faintly, a depression in the head.
Sooooooooo, now that a casting with a single digit for the year, in this case a 4 for 1964, I supposed this kind of confusses the issue of a single digit for the year of a Flint (Saginaw) casting and 2 digits for the year for a Tonawanda casting.
Oh ya, the guide plates and screw-in studs are a typical owner modification.
Comments?

Yeah.

So you are using screw in studs with guide plates to stiffen your valvetrain. Probably to enable higher revs without lofting valves.

So why the antique, heavy oil shields?