One thing to note is check and double check everything. And wash it very well, I was amazed at how much alum shavings came out of mine. They are far from "ready to assemble". Other typical clearance problems for me was pushrod clearance. Only other issues I had with fit/finish was my deck height was not even on both banks and the sleeves were slightly above the deck. I eventually sent it back to correct the deck height and sleeves and fix something I screwed up.

Customer service it top notch. Even for sending in one for repair.

Do not chase any threads with a normal tap. The use a slightly undersize tap so thread engagement is correct when warm. I chased my head stud holes and actually pulled some studs out torquing the heads. When I sent it back they put in some sort of steel thread inserts in all the holes.