I am building a 468 with 9.5-1 comp aluminum heads with 320 cc runner and 119cc chamber and a 236/242 294/302 .620/.635 112 cam. I am looking for suggestions on the size of carb that should be used for this motor. I would like one with a choke, should it have machanical or vaccum secondaries. Holly tech support says an 850 would work but that seams to big. Any suggestions would be great.