Inliners International Forums General Discussion Engines A 250 head question

I'm rebuilding my 250 in my 70 Chevy truck. The head has square pipe plugs on each cylinder, that I assume are for the smog pump equipment, that some engines had.

When I pulled the head, and tore it down, I see that under these plugs are tubes or rods that pass through the exhaust ports.

Should I remove these things? They look like they would be somewhat of a restriction to exhaust flow. I figured I could remove the pipe plugs, then the tubes, and reinstall the plugs.My truck never had a smog pump, but I have no idea exactly what year or vehicle this engine came out of. It's a non-integral head engine by the way.

Thanks in advance,
Kevin

Yes you can remove them. they started that about the mid 70s I have about a half a dozen of them heads and some only have the casting boss and have not been drill&taped yet. hope this helps }[oooooo]

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NovaMan/Twisted6/Larry

[This message has been edited by Twisted6 (edited 08-18-2003).]

I've taken those tubes out on a couple of heads, and they whistled at certain rpm ranges. I know that sounds kinda dumb, but the first time I took them out, I searched for the whistle for a couple of hours before I decided to put the tubes back in. The next head I did it on was just to test what happened the first time, and it whistled, too. I tried it on a third head, and it didn't make any difference. Just a thought.

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David
newbie #4153

I was just about to post about this whistling when I read this.I just got my 292 running in my k-10 and yes at certain rpms it has a whistling sound mainly just off idle around 1500 rpm or so.I haven't checked the serial number of the engine but there's a cast on the side of the block that says GM 1970.I realize the head could be any year but it has plugs in the top of it too.I was thinking I might have a whistling header gasket......but I guess it's what ya'll are describing because the 250 that I had just bought that was bad and I had to take back to the parts house had that kind of head on it to and it was making the same dang whistling and my older 250 that didn't have the plugs in the head never made that sound.Will this hurt anything other than an annoying sound? See ya'll ......Gerald

If a plug was installed to be flush with the inside surface would this not stop the whistling. That way the tube hole yet left inside the port would be filled. Just a thought here. Seeing i have a few of these heads myself.hope this helps & Thanks for the warning.
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NovaMan/Twisted6/Larry

The noise is just going to annoy you to death, but otherwise won't hurt anything. It sure will attract a LOT of attention, and probably a few laughs, too. What you can probably do if you don't have any of the original tubes is to cut up some solid 5/16" rod and weld it straight onto to the ends of the plugs. The whole gizmo when screwed in only needs to extend flush with the inside of the exhaust port wall to stop the whistle. If you put a tube (not a solid rod) that is only flush, or cut off the original tubes to be shorter, then it'll just raise the pitch or change the rpm range of the whistle.

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David
newbie #4153

I would think one could do the same as we do on the intake when the boss is removed and the cap/pipe plug is installed .(Drilled&tap) and blended flush with the top of the port. And not have to worry about doing any welding to the head for those That can not weld Or have someone else do it. And also this avoid any chance of the head warping. Just a little more food for thought on this matter. I had a whislte at one time But it was coming from the carb. Rebuilt it and that was gone I never did figure out what made it do that But Oh well water under the bridge LOL. }[oooooo]



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NovaMan/Twisted6/Larry

Well to heck with the engine reman company this engine came from because now I have noticed this son of a gun.......though I'd like to say it a little on the ugly side.....is whistling all the dang time under load........it only stops whistling when I ease off the gas and cruise.I don't think its the carb because I had rebuilt my older one twice and figured out it was probably warped so I bought a rebuilt one and it runs fine and as i said earlier my original 250 had the older model head.....same carb and NEVER FRIGGIN WHISTLED.Oh well I'm gonna have to fix it because I can't stand it and I dang sure know they won't fix the thannng.Thanks you guys for the insight and help........y'all saved me alot of time again at least in the diagnosis..........Gerald the whistling k-10 4x4 wit a 292.

Hey,do any of you dudes know of any kind of putty or like liquid steel or muffler compound that could stand up to the heat of the exhaust chamber?If so I would pack that crap in the hole then put the plugs back in over it just to make sure it's gonna stop that dang whistle before I go through getting my buddy to weld steel on the ends of the plugs.Thanks.........Gerald