Has anyone ever tried POR15 for a block and heads??

Are you trying to seal rust, cover it or prevent it?  I use Eastwood's rust encapsulator and it's about the same thing.   It works great, but I clean off most of the rust and scale first.  If I had a seriously rusty block or heads, I would have them bead blasted before I painted them with anything.  You can use good old Naval Jelly if you want to remove it with chemicals.  Don't paint anything over scaly or dirty parts, it will just flake off.  You may know this already, but it's worth saying for those who don't.

POR   They make an engine paint use that



"Came too close to dying to stop living now!"

I painted my flathead engine and heads with POR 15 engine enamel. This isn't the two-part POR 15, but a "hi-temp" engine enamel. It says 350 degrees on the can. The engine block was chemically cleaned, so no rust was on it. It went on good and covered the engine with one coat. I used a brush and the brush strokes evened out very well. It has burned off the intake manifold where the exhaust crossover is. The engine has been running just over a year and it still looks good. One pint covered the engine and transmission with about 20 percent left. 

Thanks everyone.  I just got the block back from a "shake and bake". We're lapping the valves now. Updated: Feb 2018.  The POR 15 went on really well with a gun after thinning just a little bit. I don't have too much run time on the engine yet as I sent the car off to be painted. This stuff is hard as a rock.