McCoy 29 sport glow head wanted

Any of the current typical long glow plugs like OS#8, McCoy 59, ecetera will work

Prices range from $2.99 up to over $27.99 per plug

I recommend local search before mail order...or try to hit the free shipping for fathers day from Tower Hobbies

Thanks for the info, I had some old plugs that looked like the right diameter and would start to turn into the head then stop about 1/2 turn in.
I did not want to force it in the aluminum,so I thought maybe the threads had a different pitch. The same plug would turn right into my Cameron engines.

I have a 1950s McCoy 29 in front of me and it tightly accepts the three spare plugs I have screwed into the four way wrench plug holders..

You may have a big mismatch...before trying to force it in I would look at the cylinder head threads and the plug threads with a magnifier to see if there is a burr or previous cross thread or some problem

Some plugs have cut threads and others are rolled and often the pitch between the threads is slightly different... I have some that can turn into my engines by finger and others in the same head feel super tight giving me pause

any luck finding a plug?