Paul, the only parts that are of any use from the 351m/400c are the conrods if you happen to decide on a 351w. At 6.58" c to c, with the pistons from a 3.25" stroker kit (302SBF) and the 351w crank in a late (9.500") 351w block they give 0.005" deck clearance.Then you fit your favourite Windsor heads on & use a couple of FE styled windsor rocker covers to get your near as dammit FE 427 look'a'like.
Jack Mac ( Oh, BTW- to make the SBF pin fit the 351/400 rod you use the small end bush from an old 272/292/312 Y-block, presses straight in and then requires hone to size. BE of rod needs to be narrowed to fit 351w crank rod journal, that an easy one with a lathe, ARP wave-loc* rod bolts & your done ) Tough old rods, I had one guy run them up to 8k in shotpeened form on a 4" crank in 351w block , rods never gave a problem but block cried enough after about a years club racing)