I would definately go with vac. sec. carbs. Without more detail's it's hard to tell you how big to go on carb's . Try this, take your 427 cubic inches times your max R.P.M.'s divide by 3456 then times it by your V.E. which on most high performance motor's is 85 percent ,or.85. Example 427X8000= 3416000 divide by 3456=988.43 X .90=889.53 C.F.M.'s