I have an opportunity to buy a Thunderbolt IV ignition “black box”. It is out of an early 90s 340HP inboard. Would this unit work well on a 89 365HP 454?

The module in the 1989 454 mag, & a 1991 7.4 inboard engine have the same part number. So that would work the same as original (same part).

Thanks for the help JIMG.

You could try a V-6 module to see if you like it. The advance curve is quite a bit different, allowing more initial advance than the Mag module.

I've got 4 v6 modules if you're interested. The advance curve is much better.

I wish I would have known sooner I would have tried the V6 version. I already purchased the 340HP one.

Thanks for the info

It never hurts to have a couple spares.