upgrading a model B 4 cylinder engine

[Synchro909]

I run a Snyder's 5.5:1 A head on one of my engines. I had to plug a couple of water ways but that causes no drama. I've been disappointed with the engine but can't say it is the head. I've checked everything. My next move is to check that the valve timing is correct. My A engine fitted out exactly the same as the B is waaaay better.