for a start I would mockup & check the "height" of the "V" (bolt hole alignment is an OK check for this on a DD) & it sounds like this is a stock rebuild) & for sure see if the surfaces (head/intake) are FLAT. vac leaks are the cats' a$$. check/mill em flat/mockup/THEN use the right thickness gaskets to get everything in the "V" lined up adequately. to Keep It Simple Sam, a slight milling should present no problems but do mockup & go from there.