Hank, heres what I know about dividing the ports on a siamese head. In around 1999 or 2000, my good friend Darren Davis who raced and set many NHRA records in several Econo Altered comp classes, was always told by both Sissell and Headrick that dividing the port would never work. He had the idea to try this many times, but always let there advice keep him from trying it. At the close of the 19990 or 2000 race season, he was about to move up to Pro Stock Truck, and leave the 6's behind and move on. He dug a Sissell lump head out of his garage, and took a die grinder and ground the brazed lumps completely out of the head, and made a simple sheetmetal divider, and tack welded them to the header flanges, so they would protrude into the ports when you bolted on the headers. He said it made 50 HP more than the very best lump head he had ever had, and set another record on the next time at an NHRA event. Now, in 2009, no one that even races a Chevy 6 in any NHRA professional class uses a lump port head at all, for something like the lump to have been used so successfully for close to 3 decades by so many, how come it is no longer used in professional racing.
