[Hedgehead]

These have the trappings of 16 heads, are dated April 68, they have screw in rocker arm studs and dual valve springs, but the casting no. is gone. see pic. Is there any other way to definitively prove what they are without pulling them and measuring valves and cc?

[johnta1]

Looks like it has been worked on.
Possibly raced?

Anyway, it looks like it has been ground on?

Look at this where I circled it, looks like a '6'?
(or even maybe a '5'?)

Probably a 16 head.

[Kenth]

Any threaded screw holes (holding guide plates on pressed stud heads) on pedestal between stud holes?

[Hedgehead]

Thanks John. Went and looked hard at that spot, sorry but I cant see it.

Kenth these are screw in rocker arm studs if that is what you mean.

['ol Pinion head]

Originally Posted by Hedgehead

Thanks John. Went and looked hard at that spot, sorry but I cant see it.

Kenth these are screw in rocker arm studs if that is what you mean.

Kenth is pointing to the possibility of the heads originally having press in studs which would have bolt down guide plates versus the style of guide plates that were used under factory screw in stud big valve heads.

FWIW, there was a local fellow in my area in the early to mid '80's who built multiple dozens of pairs of "gimme" '68-70 small valve heads into big valve high compression screw in stud heads. Each time, he carefully ground the casting numbers off, occasionally stamping other numbers on the center exhaust ports. Same fellow also heat treated, shot preened, and rebuilt a BUNCH of '58-62 rubber rods and sold them through local Trader publication.

[Hedgehead]

Originally Posted by 'ol Pinion head

Kenth is pointing to the possibility of the heads originally having press in studs which would have bolt down guide plates versus the style of guide plates that were used under factory screw in stud big valve heads.

FWIW, there was a local fellow in my area in the early to mid '80's who built multiple dozens of pairs of "gimme" '68-70 small valve heads into big valve high compression screw in stud heads. Each time, he carefully ground the casting numbers off, occasionally stamping other numbers on the center exhaust ports. Same fellow also heat treated, shot preened, and rebuilt a BUNCH of '58-62 rubber rods and sold them through local Trader publication.

See my pic two. Is that what you are referring to?

I know a lot of heads have been reconstructed, and that is mainly the reason for this post. Not that it really matters, this motor pulls like a train, even with log manifolds. I would just like to know.

[Hedgehead]

FYI, this motor had a radical (for me) cam in it when I got it, which I replaced with the 068 grind for street ability, a good move. Why would he do that with a small valve head. Makes no sense. I don't know who the builder was, neither does the PO, who bought the engine though a third party.

[rexs73gto]

The reason you can use the small valve heads is they are basically the same head as a RA head but not having the big valve makes them worth less but you can cut them for the big valves very easy & do a little port work & then because they probably haven't been abused as much as the RA head they make a good head to use. Plus theres a lot more of them out there to use for a lot less money. All the Pontiac heads are about the same just different bowl size & different size valves but all that can be changed in a machine shop.

[Hedgehead]

Originally Posted by rexs73gto

The reason you can use the small valve heads is they are basically the same head as a RA head but not having the big valve makes them worth less but you can cut them for the big valves very easy & do a little port work & then because they probably haven't been abused as much as the RA head they make a good head to use. Plus theres a lot more of them out there to use for a lot less money. All the Pontiac heads are about the same just different bowl size & different size valves but all that can be changed in a machine shop.

So even if I pulled the head I couldn't be sure. Oh well. I'm happy.

[north]

Another possibility could be factory replacement heads, if a car had a problem with a head (heads) when it came off the line they would be replaced at the service shop at the plant. They had heads that were cast without the port codes to reduce inventory, they would take the appropriate blank head (low or high compression, small or large valves) and add the right valves, valve springs etc for the specific application and then stamp the ports with a large punch set (similar size numbers as the normal raised numbers).

Maybe this set went through without being punched.

[Hedgehead]

Originally Posted by north

Another possibility could be factory replacement heads, if a car had a problem with a head (heads) when it came off the line they would be replaced at the service shop at the plant. They had heads that were cast without the port codes to reduce inventory, they would take the appropriate blank head (low or high compression, small or large valves) and add the right valves, valve springs etc for the specific application and then stamp the ports with a large punch set (similar size numbers as the normal raised numbers).

Maybe this set went through without being punched.

Could be. I highlighted the port with chalk and shined uv on it. A 6 appeared but it was recessed so I paid it little mind.

[Kenth]

Originally Posted by Hedgehead

Thanks John. Went and looked hard at that spot, sorry but I cant see it.

Kenth these are screw in rocker arm studs if that is what you mean.

Look at the guide plates.
There is two holes in the guide plates, between the studs.
IF there is a threaded screw hole beneith these "extra" holes, your heads were small-valve "bread&butter" from factory.

[Hedgehead]

Originally Posted by Kenth

Look at the guide plates.
There is two holes in the guide plates, between the studs.
IF there is a threaded screw hole beneith these "extra" holes, your heads were small-valve "bread&butter" from factory.

Thanks Kenth. No holes. I guess I got my answer.