Costs to build an engine??
Since we do not know what you had done to the motor,it,s hard to say.A refference is a 451 I did for a buddy,after every machining thing you can do,parts and labour,you looking at 6500$.Just machining,assembly and balancing and what ever shop cost there are,2000-2500$.As for machining,you need to list what was done to the block and heads,was there porting done,or just a regular valve job.What was supplied by the shop,what was not.Give us a detailed list and prices to compare,or call me about it,PM me late or look at my profile for numbers,mrmopartech