Thunderbolt IV do have rev limiters on HP 465, HP 450 & HP 500s. The rev limiter is located in a seperate box located under the amplifier with wires to the coil, distributor & module on these engines. They are set @ 5,350 RPM. The Thunderbolt V ignitions have the rev limiter built in the module.

I have an old v-drive project (BBC) that had a dual point in it. I am thinking of using the Thunderbolt IV out of my other boat ( went full MSD) w/ a Jacobs digital ign. set-up that I also have. Any input would be appreciated. Thx.