Is there any way I can put rev limiters on my stock Thunderbolt 4 ignitions? Or do I have to change to new systems such as MSD?

you can just add a revlimiter to the stock TB4. MSD, Crane, and several others make addon limiters.

I used the crane no6 boxes they have the rev control built in work fine with no problems so far.

How do theese work, do I just wire up the aftermarket limiter to my stock ignitions?

Yeah, in fact I have an unused pair of MSD soft-touch rev limiters that I never installed. I got them for a TB4 system. I verified the wiring hookup and made plans to install them. Never did.

Intention was to keep dad from overrevving when jumping waves. Lost dad to a car wreck before I ever installed them.

mcollinstn........sorry to hear about your dad. thats the same reason that I want limiters on my engines. Where can I buy a pair and what should I expect to pay?