They're different than the earlier motors, so stuff like multicarb intakes and other period speed equipment can be hard to find or even nonexistant...
Try these guys: http://www.cad500parts.com/ Though most of their stuff is for 472's and 500's, I recall reading they have some parts for 331 - 429 CIDs -Lee Atomic Radio www.atomicpinup.com
My father-in-laws old 66 cad calais is for sale at kimberly automart in davenport ia- good engine-found some parts from egge but could not find a lot of hot rod parts or multi-carb intakes or general cool stuff- but runs pretty damn good in that aircraft carrier on wheels
Put it back stock.....325 hp and 480 ft/lbs is nothing to laugh at. Granted, multi-carb set-ups add to the look, but those Cads had plenty of punch from the factory. -Lee Atomic Radio www.atomicpinup.com
4 Year only engine, 64-67. There is almost no aftermarket parts for them, but like has been mentioned they are torque monsters for sure. You can get all the mechanicals and gaskets etc... no problem...I use Rockauto.com alot. An Edelbrock 1406 carb bolts right on and is a good match for the engine, that and a pertronix kit and should be good to go.