So it turns out that the body of the plug is a few mm's too big in diameter. Will not let the plug fully sit.
I took a flap disk to one plug to see and ground down to the same diameter of the crush washer and had no issue threading the plug all the way in to the seat.
Question is, are there plugs out there with a slimmer body?
Frank, I have NEVER seen such a thing with A/C 45's. I wonder if they're the new Chinese sizing??? Are you sure they are the right plug for the head. Some of the newer heads take the 5/8ths head plug and not the 13/16ths.
I am going to pick up a different plug tomorrow and see. After all that, pulling what little hair I've got, I remember changing the heads but don't recall what they were.
Might be a conical seat, which is a thinner plug from my searches.
Frank, I have NEVER seen such a thing with A/C 45's. I wonder if they're the new Chinese sizing??? Are you sure they are the right plug for the head. Some of the newer heads take the 5/8ths head plug and not the 13/16ths.
Thats my thoughts to. The 5/8 plugs are probably what you need.
The larger plug (R45S) has a flat seat in the head and uses the gasket and the smaller plug (R45TS) is a tapered head and uses no gasket so check the head and you will tell which plug it uses.
Picked up a set of AC Delco R45TS, they are in and now to get the plug wires on and looking neat.
It's good to hear the R45TS plugs did the job for you and they are the right plugs for that cylinder head. I wasn't sure which heads you were using until I looked at the washers on the plugs in your picture. The washer compressed into a taper indicated that you had a tapered seat head.