This kid I know just bought an 81 S&S hearse with a 368. I've never heard of a 368 let alone seen one, however I'm quite versed in the chevy small blocks. The car is in real good shape for being 24 years old, and it runs/drives good for the most part but it seems to be leaking oil from age and I believe one of the freeze plugs on the heads is leaking. We're in the process of pullling the engine to clean it, reseal it, paint it and replace all the vacuum lines and such. The biggest problem I'm running into is the emissions controls. The diverter valve is melted and the tube the runs from the valve to the cross-tube on the heads is missing...someone had a stick shoved into the hole to quite the exhaust noise. I've been to several parts stores here in Nashville and have searched the web but no one lists anything other than the check-valve. Another odd thing..this car had to go through emissions testing to get registered, it passed on the second test, but in checking this thing out the hose from the air pump was disconnected, diverter valve burnt and the air tube to the catalyitic converter is burnt in two.
If anyone has a clue to where these parts can be had please let me know.

That A.I.R. pipe that goes between the front of both heads was used for many years. They probably vary somewhat but there has to be some laying around somewhere. The check valve that threads onto the inlet is still available all over. You might want to take a look at a dead HT4100 car and see if you can adapt the A.I.R. management valve over to yout 368. The engine management is pretty much the same. Look for '82,3,4 and 85 RWD with the HT4100 badge or just follow the light brown mixture of whipped up oil and antifreeze trail.
Good luck.

The pipe between the heads is still there, it's the tube that goes from that to the diverter valve that I'm missing.
I'd have never guessed to look at the HT4100's...looks like I'll be hitting the junkyards next week. Thanks for the info.

sorry to drag this old thread up but my air tube/pipe is broken in half on my 1981 cdv. I too have a 368 and am in need of this air pipe. If anyone has any suggestions?

I thought a lot of the parts from the other big blocks were the same, the
425,472 and 500.

If any body has this part (the air tube in front of the engine) or knows of where I can get one, or knows of a work around ?

I think the one for the 472/500 is different than the one for the 368. Not sure if the pipe on the 425 will fit the 368. From what I have been told, the heat and moisture rots these pieces out (like on old exhaust system)

Maybe check with Inline Tube or Classic Tube to see if they can bend a new pipe of the same diameter. If they can, you would probably need to duct tape the two pieces together, pull off the the pipe as one piece and have them bend you the piece. The only issue would be the ends where they go in the engine.

On the HT 4100, the tube actually is powder coated and threaded into the exhaust manifolds. As said before, it uses a similar diverter valve setup, just the plumbing is different