compression numbers. Engine has maybe 25 minutes run time all out of the water with no drive installed.

1 = 170
3 = 165
5 = 168
7 = 168
2 = 172
4 = 170
6 = 170
8 = 172

The oil in the pan is slightly milky. I can tell from just looking at the dip stick.

I ran the engine for about 15 minutes this AM and it would not heat up. Hottest it would get is about 100 degrees. I have a 140 degree thermostat. I am running a crank mounted water pump and I have a water pressure gauge. At 650 RPM the water pressure gauge read less than 10 psi. When revving to a max of 2500-2750 the water pressure gauge would come up to maybe 12 psi.

An exhaust leak can cause this. It did on mine on brand new exhaust. In my case I had to resurface the risers mounting flange. It could also be at the head to exhaust manifold surface.

If you have any plugs that are wet, then maybe intake

Fella on another forum with fresh rebuild stock motor and stock exhaust had water showing up. Then timing was set correctly and this went away. Strange even for a stock motor even if its out of time a bit, but I'm just spit balling

I can’t see this being a cam issue unless it is installed wrong. You .006 overlap is only 48.5 and .050 is -3. Try advancing the idle timing some. That may help

Is there a way to determine if the cam was installed correctly without removing the engine and going back through the degree'ing procedure?

650 rpm is pretty low. Turn it up a little bit at see what happens.

On a hose your not going to get much pressure, the hose is unable to supply enough water at anything other then about idle

I think you have something else going on with water or air leaks or maybe even some bad condensation.

Your cam installation should be fine the way you described everything. You did the math and found that dot-to-dot was good... I wouldn’t be worried there.

I’ve run small blocks with a heck of a lot more cam and less riser and never ran into reversion.

Make sure your risers are sealed up tight. I’ve used high-heat RTV and gaskets to seal up SM risers (the surfaces can become pitted and cause air leaks that in turn create a vacuum). As mentioned earlier, make sure the head to manifold surfaces are sealed well too.

Aside from the exhaust, look for a leaking intake or head gaskets (as mentioned). It doesn’t take much to make a mess of things.

Couldn’t hurt to pop off a valve cover to see how much water is in the oil.

What are the air temperatures like where you’re working?

Bump the idle to 750.

I would bump it even further. If too low of idle is in fact causing an issue it will continue to be an issue when you put it in gear and the idle drops 150-200rpm. I run Small block LS engines in my Daytona. My idle is set at 950 in neutral, drops to 650 in gear, and recovers to 800. Granted I was running a much larger can which hurts my idle more (237/252 113+3). I was also running 22 degrees ignition advance at 1k and below via an msd box to stabilize idle. My point is bumping the idle will help a lot with reversion if that is the case. Just keep it below 1000 to not injure the outdrive. Also, double check your cam timing and validate your ignition advance is correct as well as the balancer marks are correct.