Here's what I like to do. Go to compcam.com and look for the camquest link and down load it. Get ready to spend a lot of time as it is very addictive, well for me it was. It is fun to use though.
First you need a block. If you already have one, check for nickel content, a 10 or 20 will be displayed under the timing chain cover any where in the number system, and will contain 2% nickle and 1% tin. Very good block. Then you have to make a whole bunch of decisions(this is where the camquest will come in to play) Do a whole bunch of research BEFORE you buy anything. Go to scat .com, visit eagles site for a good rotating assembly (cranck rods and pistons. I would recomend all forged parts so if you want to later you add any thing you want such as a blower, nitrous, highrise or any thing that would produce in excess of 500 HP GO BIG on the bottom end and you'll do great. Next have the block checked for cracks, again do your homework and find a GOOD machine shop that does race motors so they'll know what your intent is. I would deffinately deck it for a flat head surface. If you get this far you'll know as much as you need to about this procedure.
Good Luck