[Vid]

Dang, well this can’t be good. Today I was taking apart those cool “upside down” 62’s I bought about 6 months ago, getting them ready to go to the beauty shop for the full deluxe spa treatment including new stainless valves and a gorgeous porting job to compliment the custom cam I just ordered from Tim over at Bullet/Ultradyne.

Everything looks great until I remove the one of the last 2 intake valves. Valve feels a little bit sticky coming out of the guide (all the others glided out smoothly) take a gander only to discover a bunch of rust in the port and on the back of the valve. Fudge.

Probably a crack somewhere. The seller (who is fairly local to me and seems to be a decent guy) said that they were stored for several years, so maybe if I’m lucky some moisture seeped into the port during storage.

I guess I can still bring them to the shop and have them magnafluxed and pressure tested but dang. Not what I wanted to find, LOL.








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[tom s]

Have it pressure.Tom tested

[tom s]

Darn,something like that!

[steve25]

It’s no big deal, you want to install bronze guide liner sleeves anyway so tack that on your beauty shop list.

Of more concern is that fact that the chamber walls on the plug side have been layed back a dam good amount and the sharp change in angle needed to shread wet flow rivulets on the out the side of the runner are no longer there, there are gone!

This will make for a bit less efficient combustion and a larger chamber volume then the normal 75 to 78 CCs, so you should CC at least two chambers in each head to see where your at before ordering pistons.

Also from what I can see many of the intake valve seats have been badly sunk from previous valve jobs and this will cost you reduced high lift flow numbers.

Here’s a picture of what chambers look like stock.


If I where you I would look into Ferrea making you 8 custom 2.14” valves to nearly resolve that issue.

I have done this many times and when the shop does the valve job they can at the same time bowl port the intake side for you, and the small stock valve bowl throat size of 1.600” is where the main restriction is in all the D port heads.

[Vid]

Originally Posted by steve25

Of more concern is that fact that the chamber walls on the plug side have been layed back a dam good amount and the sharp change in angle needed to shread wet flow rivulets on the out the side of the runner are no longer there, there are gone!

Thanks for your input, much appreciated. But I’m trying to absorb exactly what this paragraph means. I think you lost me at the wet flow rivulets part?

Also, nobody likes the Milodon valves huh? Everyone likes Ferrea?

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[Vid]

Originally Posted by Vid

Thanks for your input, much appreciated. But I’m trying to absorb exactly what this paragraph means. I think you lost me at the wet flow rivulets part?

Also, nobody likes the Milodon valves huh? Everyone likes Ferrea?

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Ohhhhh, yeah I studied your picture and now I see EXACTLY what you are talking about. Dang. That defined ridge on your photo is NON EXISTENT on my heads.

You know I really want to be an advocate of preserving the old parts and keeping the stock look and all that jazz, but I see the money really adding up on these cool old 62’s. Maybe I should just cut my $500 loss on them and go aluminum. I’m gonna say FUDGE again.


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[steve25]

On the roof of the port from the valve guide on out thru the valve bowl fuel mist ( mist is a good thing) during high air flow rates can collect and form into little rivers .
Little rivers of fuel do not mix with air to burn properly.

The Cause of these little rivers is too technical to get into here!

The abrupt change in the original rear walls of the chamber serve to shred those little fuel rivers back into a burnable air and fuel mist.

I have used Milodon valves before and there good for even a strret / strip build , but in terms of custom valves it comes down to Ferrea or Manly for me.

[b-man]

Probably a little water got in there during the time they were sitting in storage. Pretty common actually.

Doesn’t look at all like something that occurred during operation.

At the most you might need a seat installed if the valve seat doesn’t clean up during a valve job.

[Jay S]

Lol, b-man treed me. I agree, Looks to me like when the engine was sitting before the heads were pulled it got some moisture in it and that rust came from having the valve open. Happens all the time, doesn’t at all mean it is cracked. Valves don’t look sunk to me? Hard to tell that looking at a pic, whoever does the valve job will be able to tell. I use 2.125” Chevy valves to go bigger. Cheap and you can find them the right length, easy way to go from 30* valves to 45* on the intakes. Milidon mega flows are good valves, so are Ferrea, and Manley.

[67Fbird]

hmm...learning here, as I too am about to put together a set of #62...maybe. Yeah somebody got a bit happy in the chamber on those.....probably 90 cc now instead of 75. Interesting note on the Chebby vlaves??????

[Vid]

Originally Posted by 67Fbird

hmm...learning here, as I too am about to put together a set of #62...maybe. Yeah somebody got a bit happy in the chamber on those.....probably 90 cc now instead of 75. Interesting note on the Chebby vlaves??????

You know, I did a rough measurement of the chambers with a graduated syringe using the “plate glass with a Vaseline seal” method and the average was only 73cc. Now when I say rough it was rough but I don’t think I was 20cc’s off. I’m guessing that these must have been milled once or twice in their previous existence so the grinder giveth and the grinder taketh away?

I’ve looked real close at that area in question and have to wonder if it was in fact done intentionally or cast that way? It seems extremely consistent from one cylinder to the next and I don’t see any kind of marks left from an abrasive source. Probably no way could it have just worn down naturally from many years and miles of use. I don’t know guys. I’m perplexed and I’m still taking a harder look at the new ones made out of recycled Pabst Blue Ribbon cans, LOL


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[steve25]

Chambers are fully machined and would never look that way stock.
1) Did you CC then with all the carbon build up still on them?
If the heads did start life at 75 CCs it would only take a million of .012” to bring them to 73 CCs.

[JLMounce]

Fwiw here is a shot of the chamber on my old 62’s. You can still see the prominent edges on the plug side. Yours have definitely been laid back.

[steve25]

Yes Jayson as in my picture which is a 62 casting also.
Vid, you should also note that in Jason’s picture the intake valves are the stock ones with the round little dish in the middle of them unlike yours.
This dish adds near one CC to the chamber volume.

[67Fbird]

what a bad one looks like ....
https://nastyz28.com/media/ta-head-with-holes.8484/

[67Fbird]

me and pictures here just do not get along..

[1968GTO421]

Originally Posted by 67Fbird

what a bad one looks like ....
https://nastyz28.com/media/ta-head-with-holes.8484/

Wow, that is one sorry looking head.

[Vid]

Originally Posted by 67Fbird

what a bad one looks like ....
https://nastyz28.com/media/ta-head-with-holes.8484/

Wow! Mine look like a million bucks compared to that! Haha


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[Vid]

Originally Posted by steve25

1) Did you CC then with all the carbon build up still on them?

Yeah they were dirty with carbon when I measured hence the “rough” measurement. I was after a ballpark cc figure and I’m fairly satisfied with that.

I’ve decided against using these heads for this 455 build and will purchase a pair of new aluminum heads. It just makes the most sense and I’m going to sleep much easier tonight.

As for the upside down 62’s, I’ll have them assessed by a trusted shop. If the shop says they pass muster and could be made functional without tremendous expense, then I’ll proceed and have them freshened up because they actually are a rare and cool little nugget of Pontiac history.

I have a low performance 350 waiting in the wings to be rebuilt, the 62’s should be right at home bolted to that. If the 350 suffers from somewhat compromised combustion it won’t bother me at all. On the other hand, if my new 455 build never runs as good as it should well that would frost my cookies


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[LStathas]

I don't like the look of those two boogers next to the valve guide. Maye hit water and brazed up?