Texaco prop spacers

Cox International wrote:We are looking into manufacturing spacers for Texaco engines/props.

The OEM Cox one will not work with the 8x4 props as it is too small. It was designed for the Cox 7x3.5 prop.

What props are used for Texaco events? 8x4?

If also 7" props, would it make sense to design the spacer for the 8" prop; whereas a 7" prop could be reamed to accommodate the part?

I am pretty sure in texaco you put on the biggest prop you can!
"1. 1/2A Texaco:- Model must have been designed by December 31,1938 and shall be powered by a glow ignition engine of .051 maximum displacement. Engines may be reed or rotary valve induction. Diesel and diesel conversions shall not be allowed. No size or weight limitations. Model may be scaled up or down from the original. Construction shall follow the form of the original. Wood sizes may be scaled to agree with the model’s scale. Only alcohol based fuel may be used. A maximum of 1/2 ounce of fuel is allowed. The contest director may specify a smaller amount of fuel if conditions indicate engine runs should be limited. There will be no maximum flight times. The use of a dethermalizer is at the discretion of the flyer. Timer goes with the contestant. Releases may be ROG or Hand Launch as declared by the contest director. Three official flights are allowed with total accumulated time used to determine placement. Three unofficial flights (attempts) will be allowed. A flight of two minutes or less is an unofficial flight unless declared official, by the contestant, at the time the flight terminates. Timing starts at the moment of release and ends when the model touches down or can no longer be seen by the timer.