I googles and search forum, to my surprise I cant find external threads size used on the Q Cherry Bomb? Or I missed it?
Please point me to the source.
Thanks.

I would be nice if there was a list of the specs for all the different models and brands.

I measured them a while back and they were definitely an oddball size. OD of the thread was measuring around .890" with a 24 TPI pitch. I've never heard of a 57/64 - 24 thread, but I'm not surprised they wouldn't use something uncommon to make it more proprietary.

Best bet would be to measure the threads over wires to get the pitch diameter. Searching shows it's thought to be a 0.900-24 UNS thread.

.900-24.

The taper is 25° included

I have just decided to invent a new thread....maybe I will use a fractional amount for the TPI, a non-linear taper, and progressive minor diameter thread depths... just to make generations of later machinists curse my name!

Or you could use the metric thread M23 x 1
Od 23 mm
Pitch 1mm

Ahh, I see someone else has owned a British car!