Welcome to the western hemisphere-
there are several paths to go down with the BBC---------at 454 cubes they are big enough to get gobs of horse power / torque and if you want to race the blocks are strong enough to hold 8 - 900 hp reliably. If the crank/block you have are 4 bolt mains and forged crankshaft, I would suggest that you pick a nice set of alum heads 0( Edelbrock, afr, dart,etc) to not only save weight, but get away from the valve seat/unleaded fuel issurs and build it up for a hp level of 5-600 with comparable torque----


However, if its a 2 bolt block---you can convert to center 3 caps splayed bolts and stroker kit and go up to the 500 inch area for a reasonable amount.