Carbs are the BJ/BK 2 x 4 set up that are available in reproduction for big $$$. Orig. carbs are worth as much if not more if they are in rebuildable-good condition. Head number [C4AE-6090-H] does not show in my books, are you sure the number is correct? A C3AE-6090-H head is a late 63 427 lowriser. If the C4 number is correct I'm inclined to think the heads could be passenger car head and nothing special. What is the block number and casting date? Also check for maincap crossbolts, if it has the crossbolts more than likely its a 427 but be aware it is possible to cross bolt any FE and that makes it look like a 427. Only way to tell for sure is to pull a head to measure the bore/stroke and drop the pan to see what rod/crank is in the engine. Most H/M 427s had steel cranks and Le Mans rods. One last thing...be sure its a real sideoiler and not a block that was cast as a S/O but drilled for a centeroiler, some marine/industrial FEs [and not just 427s] were cast as S/Os and are infact center oilers. Look for the galley plugs in the galley 'bulge" The counterfiting is more common than you think, I'm doing a 427 C/O for a fellow that thought he was getting a S/O because he saw the galley bulge but didn't look for the galley plugs, needless to say he is a "little" dissapointed.