350 Head Identification

[Chaoszen]

I was looking at the heads on my 350 the other day and noticed a cast indentification symbol. It is the verticle bar over rectangle. Which is supposed to be a 1957 Corvette 270 HP, 9.5:1 CR. Does anyone know anything about these heads? I had never seen that symbol before. Any info would as always be appreciated.

[JayB331]

Should be a 997 casting number. I'm not positive, but I think they have 1.72" intake valves, 1.50" exhaust valves, 59cc chamber. Good head for a slightly modified engine that should yield decent performance and good economy

[72freak]

To be 100% sure on what you have pull one of the valve covers or both and get the cast number. All the info you need can then be obtained from running it.

[geezer#99]

Not '57 corvette heads.
Look at the bolt holes in the front of the heads!

[too much stuff]

Originally Posted by geezer#99

Not '57 corvette heads.
Look at the bolt holes in the front of the heads!

X2 on above, look like standard 350/307 heads

[hugger6933]

I think the addy with all of the casting info you could EVER need is at an addy like nastyz28. com if I am remembering right. There are others though that can help you identify the heads. If you would take the valve cover off and copy down the casting number and put it in this post I sure some here would help you with a decode, some guys like that stuff. Like motor detectives or something. Jim

[TBONE1964]

http://www.crankshaftcoalition.com/w...identification

There might be some information in this link that will help you. The best way I know is to pop a valve cover and get the casting number and the date code and go from there.

[D.PASSMORE]

You can get a base idea my matching these marking with a few charts on the above website.

[mmiddle]

The fact that they have accessory bolt holes says they are 69 or newer.

The good iron heads have one or two humps. If you find a set that have only one hump hang on to them... they are rare. Those are over-the-counter "292 Turbo" heads.

[Chaoszen]

The mini mystery deepens. The casting number on these heads is 1668668. It also has a stamp of GM 65. It has the vertical bar over rectangle pointing at the casting number between the valves as well as the vertical bar over rectangle on the front of the heads. I have not been able to find any info on casting number 1668668. I'm stumped.

[Chaoszen]

Here is a closer shot of the head symbol. The same symbol is under the valve cover pointing at the forge serial number. #1668668. Also a forge stamp that reads GM 65. And a couple of other photos.

[bruceman1968]

Any chance you might have read that number (1668668) upside down and backward, with a misread on the last digit? That would make the head casting number 3998991. If so, then they are...307/350, 68-79, 1.72/1.50, 76cc Heads.

[Lee H]

Nice work Bruceman, that would make them the so called light weights. I've been pouring over my books and docs for a few hours.

[Chaoszen]

I was wondering the same thing. I had my neighbor read off the numbers for me while I wrote them down. We were looking at the facing front passenger side from the top of the head to the bottom. Could be as those numbers don't make sense. But the GM 65 was read the same way. So it would have read 56 MG looking at it the other way. Doesn't make sense. But the verticle bar over rectangle seems only to be from 1957 as far as my research goes.

[Lee H]

What is the date code on the head? It would be a 4 digit code something like F137 under the valve cover similar the the casting number.

[Chaoszen]

Thanks everyone for helping me try to figure this out. I didn't build the motor and am trying to figure out if I might want to buy some better heads.

[mud.man.rj]

No matter what with acc holes in them makes them a lot newer than the 50's or early to mid 60's. So forget about the early corvette part.

[Chaoszen]

There was a four digit number aswell. But I didn't think to write it down as I thought the 7 digit was the one I needed. I will take off the valve cover again and look.

[bruceman1968]

Originally Posted by Chaoszen

Could be as those numbers don't make sense. But the GM 65 was read the same way. So it would have read 56 MG looking at it the other way. Doesn't make sense.

It doesn't make sense if your talking about writing something down on paper, But it makes perfect sense when your talking about attaching number plates to the core of a mold, which is made up of several sections
Have your friend read it again from the other direction and you'll see that 8 turn into a 3, and the number will be 3998991. Trust me on this one I seen the ol upside down and backward read plenty of times. 6's look like 9's 3's look like 8's and 5's get read as 2's and 7's and 1's get misread also.
Your Gm 65 identifies the mold as number 65 and GM is of course GM.