Hi
I'm assuming your in Denver...Years ago I built a 401 Stroker, that put about 480HP to the rear wheels...It did an 11.4 Q/M @ Bandimere Speedway In street tires, with capped headers...I used the 401 block & Crank, but with the 390 Rods.(Slightly longer stroke) Then the 390 Dog Leg Heads, Crane Triple Battleship Springs, 568 lift on the Cam....I had the block,rods, pistons, and crank, machined at "Gunn Automotive Machine Shop" On South Federal Ave in Denver...However they DID **** the heads up, (badly) and I had a Guy re-do the heads to the tune of about $3g's...He was an absolute "GOD" with those heads...His name was Scott Maine, but I'm not sure if he' still in business....MPG Heads was his shop, in Littleton...As far as assembly, I did all that, and it wasnt any more difficult than building any other engine, but yes, detail is always important in assembly process....I could not have been happier with my results though...That car made alot of big block Chevy, and Ford owners, VERY unhappy....
I should add that Gunn Machine shop, is actually an extremely capable shop...They have been around, a VERY long time...