I've never had an issue with multiple parts house rebuilt items. I'd get an 8 blader and tack an anticav plate on the vanes. use a small of WP pulley as you can bearing in mind that an unmodified pump will cavitate at 4000-45000 pump rpm and a cav plated one at ~5800-6000 which is a (high rpm) race consideration only as street you'll be much lower and I am a firm believer in as fast of water speed as you can muster. Support the shaft at the "cross" side and press the vanes in compressing it till you have ~.040" clearance. On the other side if the timing cover is off you can mill the front face to get .040" clearance between the cav plate and the "flat" of the tim cover keeping mind the thickness of the gasket then use shorter WP mounting bolts or washers and space the pulley out from the cross to restore alignment and inside the 2 tim cover water holes there's a casting parting line that can be smoothed w a die grinder/dremel in 10 seconds. If the heads are not assembled PM for some block/head water passage mods/additions