Ken,
You are going to want to research your springs according to which cam you use. Things like coil bind height and and clearance at maximum valve lift are going to be new factors.....really research what it is you want to do. Start with a realistic goal and come up with a plan of how to get there. Doe sit fit the budget for time and money? Can parts be put back into service or do they need reconditioned? Remember that bigger is not always better in carbs and cams. The basic idea is to increase cylinder "fill", the amount of air fuel mixture during the intake cycle. The most overlooked way to do this is port velocity. More air/ fuel can be stuffed into the cylinder if it is moving faster.The increased density within the cylinder raises the cylinder pressure which when ignited creates more power. Cylinder pressure can also be increased through cam timing. The point at which the intake valve closes determines the usable part of compression ratio.

I know I am throwing a few ideas at you in really vague terms, but it is up to you to research and learn more. These guys are really knowledgeable but do yourself the favor of researching as much as possible before buying any parts. Do not modify anything until you know why, and where it fits into your plan.