Build the bottom end for the boost you are going to do. If you buy a stroker kit get the forged crank and good rods. Compression needs to be low but flat top pistons and open chamber heads should be good for 6 psi boost. More boost may need dished pistons. Boost is increased with a pulley and belt change. If you are using a stock 454 steel crank and rods, put ARP rod bolts in. A four bolt main block is not required but it will help keep the mains clamped if you go high boost. A good machine shop can convert the 402 2-bolt main block to a 4-bolt. For extreem boost use ARP studs instead of bolts to hold the main caps down. Have the rotating assembly balanced. Remember that stock 454s were externally balanced while 402s were internally balanced. So you need to have the machine shop do an internal balance if you want to use your 402 balancer and flywheel/flexplate. You probably want to pick a blower grind for the camshaft. Blower blow-through carb is needed. Don't forget the boost valve. Procharger has great intercoolers but then you have all the plumbing issues and mounting the intercooler in front of the radiator can be a challenge.
Personally if I were going this route, mainly because I'd have to have a fat wallet to begin with, I'd go with either a 454 block and stroke it to a 496. Or even beter, go with an after market block and get huge. Blowers and cubic inches go together.
