Leak Down Findings

Well Norm, at least now you know. I agree some crankcase leakage is normal, especially on an engine that has not fully seated yet..However, you have valve issues. If it were me, I would continue with the small block until it goes right. Pull the heads, see what the pistons look like. Are they bent, or just poor seat work? They obviously need help, and existing is always cheaper than a swap. Plus, the 440 may be claen, but doesnt sound much better. I'd ge the heads fixed properly, take the opportunity to address any other engine problems whiel it's apart. Then do the 440 over while you beat the tar out of the 340..lol.