[davedrivesody]

I'm wondering if a Fumoto 14-1.5 will fit in the new threads?

I doubt it. The oversize Dorman has expanded the thread diameter. At this point, I think any standard 14mm will strip out.

Going forward, I think you are committed to the Dorman.

So far it has held for one full torque - a good sign.

 

[davedrivesody]

I guess nominal sizes can vary.

The nominal 14mm size is the same; it's the actual size that varies.

Selecting by uniform nominal size ensures that the oversize plug is the correct replacement for the stock plug.