So my son and I are working on a 1976 Ford 302. I built this engine about 30 years ago with the intent of creating a Cobra engine (Cleveland 351 heads on a 302 block). Unfortunately the salvage yard sold me a pair of 351M heads which were used mostly on trucks. However, to make that work, coolant flow is different through the 351 heads so an additional hole was needed in the 302 deck to match up with the coolant channel in the head. We are now going to get rid of those 351M heads and go with a pair of AFR 165s. I am assuming we will need to plug those holes in the deck since there is no corresponding channel in the AFR heads? Any thoughts on how best to do this would be greatly appreciated. Small freeze plug? Have it welded? Thanks all!