The single plane Duntov intake that has the runner that run's from each bank in the back is a good one if it is tuned properly. It supposedly keep's those two runner's from robbing each other. Thus balancing the air supply port to port. pdq67
I realize it's too late to help because it's already out, but why didn't anybody suggest drilling the center out, and using an easy-out, with heat?
I have 2 Holley Strip dominator single planes with the winters logo. They must have cast them for holley for a period of time.
when it comes to stubborn shit like stripped threads, broken bolts and other messed up stuff , just take your time and will work , leave the BFH in the tool box , be like a Honey Badger and fear nothing , persistence pays when shit is screwed up,