for your question (a bit more than stock, long block), I'd first suggest getting a how to rebuild book and read it. Determine what you really want from the engine. Then I'd research local builders. Find out who does quality work. Often, the budget racer will be under too much money pressure. The guy that does class racers or higher end stuff is a better choice (don't want to step on toes here, but the guy knocking out claimer motors is either going to make up his fees on the one-time guy, or lowers his standards across the board).

Go to the shop and see how the customer is treated, the parts are treated and where the motors are assembled. If it's right next to the grinding wheel and flywheel surfacer, RUN!