If it blows anything out from the cylinder to the intake pipe, it sounds like the camshaft timing is wrong or the intake valve is stuck. If the compression is good, camshaft timing seems the most likely problem. Probably the intake valve is staying open during the early part of the compression stroke, due to late valve timing. (When the timing jumps, usually the crankshaft finishes up ahead of the camshaft). If the timing has jumped, you have a loose belt - don't just re-time it and restart it.
I once had the timing chain jump on a car (a ludicrously worn-out ex-cab), right at the point when we set out on a drive from Perth to Melbourne. The car would then only go 35 mph, so we stopped in Kalgoorlie and took a look. By then the exhaust valves were small and square, and a couple of the valve seat inserts had fallen out. Continuing to Kalgoorlie was not a good decision. (With old car engines the camshaft drives the distributor, so it had very late ignition timing when the roller chain jumped on the sprocket. That was the main cause of the low power and high combustion chamber temperatures.)
