422 dyno fail

Let me rephrase. Early cast OE heads have wet holes in all 4 corners. Ask me how I know? Haha
True the corner exhaust mounting bolts are wet, but you should never have water/rust in the exhaust ports especially with the short run time you have on that engine. I still say more analysis should have been done i.e. your ignition system is proof.
Many moons ago I dyno tested engines for a living a you have got me lost.
I will be watching for good results.
Much luck
Jim K