Replaced inlet manifold on Chev, and engine made hideous screaming noise on fireup. Checked accessory belts, all good. Removed belt to see if it was bearing on accessories, all good. Checked distributor, a bit sloppy, so reshimmed and replaced, all good, noise still there.

A really high pitched metallic shriek when it fired up. Was just starting to strip it down again when neighbour (a dude who has been around engines since way back when) suggested air leak. Sprayed CRC around manifold and fired up. Noise gone until CRC all got sucked under edge of manifold and disappeared, when it suddenly came back again.

Went back down to different parts shop and got thickerest inlet manifold gasket, ignored end gaskets for bead of silastic, rebuilt with plenty of hylomar, and all is suddenly quiet and runs well.

The lessons here:-
1/ Chev inlet manifolds are b(*&stards, that need very thick gaskets at the side and nothing at the end.
2/ When you change one thing, and a nasty noise erupts, the one thing you changed probably caused it.
3/ Old neighbour dudes who have been around cars for ever are worth their weight in gold (or sites like this).

In saying that, it still makes some nasty noises (bubbly noises when turning over), and funes alot, but I don't want to thing about that while it is still actually running.

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Keep the shiny side up, and the greasy side down.

G'day Jabba,
Another problem with Chev smallblock inlet manifolds is if the heads have been shaved, the heads have been lowered and the manifold does not line up any more. That could have been your problem.
Cheers,
Pete.

Old Holdens never die, they