Pulled the engine, replaced head gaskets, sealed up the engine, put it back in the car and it started right up. yay!  Bad news is that I hear a knock while it is running.  First thought it would go away after oil started distributed around the engine but still there after 10 minutes.  It is actually fairly loud.  Louder than the rest of the normal engine noise.

 

Any ideas what may be causing that?  Thanks for any help!

Not sure if this will work or not, attaching a short video of noise it is making

Ok, looks like I can't upload a video.  I do think the noise is quieting so maybe it was just lack of oil!

You may have sticking lifter.  if noise persists, try draining out a quart of oil and add a quart of automatic transmission fluid.  Run that for couple hundred miles and see if the noise goes away.  If not, you may need to dig in to lifter problem.

 

Another possibility is the oil pump is not working properly.  Oil pump reseal or replacement can be a solution.

Thanks Dee2 for the advice. If it gets noisy again I'll try the ATF but the noise quieted way down to what I expect.  Maybe that noise was due to a lifter.  When I had it apart, one of hydraulic lash adjuster dropped out while I had it tilted on the engine stand and it lost some oil. Not sure, maybe it needed a while to pump that back up?  Anyway, feeling much better, everything seems to be working at the moment. 

 

Will take it for a spin tomorrow hopefully and after that I'll teach my kid how to drive a clutch

Lifter tick can be surprisingly loud, but it is a thin mettalic tapping clicking kind of sound.

 

It may come and go for a while also. Rod knock would be a deeper sound.

Ah, maybe it is more of a click than a knock.  I tried adding video to flickr, hopefully this works:   https://www.flickr.com/photos/158343911@N05/27396832117/in/dateposted-public/