The questions you need to ask are what is in the engine for the money? What improvements do you have over OE ?
*Piston brand and make up
*rings ( cast , moly , chrome)
*Bearing type (tri-metal, aluminum)
*Crank undersize limits(.010,.020,.030,.040 ,.050)welded shafts
*valves(new, reground, oversize stems,undersize stems ,valve guides)
*Valve seats ( Hardended for unleaded fuel)
*Valve springs ( new , used)
*oil pump ( rebuilt, new)
*timing set ( new, brand)
*head gasket and finish out set( Dana, Felpro,Corteco)
*pushrods ( new,used)
*camshaft ( reground, new,used , make )
*sheet metal , oil pan, timing cover,side cover included ?
You get what you pay for