SB 360. I have some Dorman 1&5/8" & they practically fall into the block openings & the freeze plug OD is a bit wavy. I did grab one dorman 41/64 which is a hair larger just to see if it would fit & if so then I would get more of that size IF they are available in a thick (wide) version (like the 1&5/8's are that do not fit). is there a better brand that fits tighter? I could go brass if they tend to be tighter. thank you for your time.