When mocking up my 261 block, I noticed I had two different styles of gaskets on hand. One, typically made by Best Gasket (first image) shows some of the holes towards the front of the block covered or restricted (NOS gaskets like the Victor 3210 seem to have this same feature unless they were marked as for 1954 block); the other gasket, made by Fel Pro has provisions for all hole (as mentioned, the one I saw for a 1954 block matches this). Any reason for this discrepancy? I want to use the correct gasket but I am confused. If I had to guess, it seems after 1954, they restricted or blocked some of the holes on the front of the block to force more coolant flow to the rear of the block, and as such, I should use that one. As a note, it appears I have a 1960-1961 block based on full flow oil provisions as well as casting number. Any help would be appreciated.
