I agree with all that has been said. One of the things I see lacking is checking clearances of moving parts, like piston to valve, spark plug to piston, rods to cylinder block, etc. Always do a mock up and check the clearances with clay and feeler gauges. I have seen a lot of so called high dollar engines that failed due to the lack of checking these simple clearances. If you are going to advance or retard a camshaft, you have to know how much piston to valve you have, advancing a cam reduces intake valve clearance for example. Also when checking piston to valve clearance make sure the pockets in the pistons are large enough in diameter not just deep enough. Just because it rolls over on the engine stand does not mean it will not hit under power when everything warms up.