I would suggest a steel drum available from any sponsors on the board. They are all competitive in price.
An engine rev limiter will have no real effect on drum failure. If anyone took my previous posts that way, I guess I need to clarify.
The drum fails from exceeding its designed rpm limit. The only real way to get to that rpm is with gear multiplication. When the sprag fails, the drum is instantly accelerated because the low gear set in the trans comes into the equation. Low gear ratio is 2.45 :1 . So, engine rpm x 2:45 = drum rpm.
My idea was to add a drum speed sensor. With normal transmission operation, the drum speed should never be higher than engine speed. If drum speed would exceed engine rpm, the engine would be shut down regardless of engine rpm if a drum speed sensor was a limiter input.