Is it worth the expense. I am building a copy of a 525SC except bigger cam.
Crane Cams HI-6M Multi-Spark Marine Ignition

I am adding acouple to my 500hp motors taht are at 565 hp
reason are programed ignition curve and adjustable rev limiter

i have heard they are one of the best.... i will either get those or the msd ones..

Built a 575 SC clone, I have been using the Crane for several years. Go with the Crane.

Thanks for the info. I will place my order tonight.

Been running one for years (except last year of course!) I like the dial in rev limiter. Using an MSD distributor with mine.

I have the MSD billet distributor with an MSD crank trigger system and use the Crane Hi-6M ignition box. I have had the Crane boxes for about 5 years now, and one got drenched with water sprayed on it from a hose that sprang a high pressure leak. I have only about 65 hours on them, but after 5 years they are still working fine.

The nice thing about the Crane is, it plugs into the Merc distributor.

I am about to order one for my Caddy 500.
I'm happy to see it is working well for everyone else.

I did mine last year - I remember having to redrill the rotor to "phase" the rotor for the Crane - no big deal and they give you the template to drill the new holes in the stock Merc rotor- only problem will be if you ever switch back to the OEM system you need to switch back to the OEM holes -

*** I purchased this set up so that I could also get the ignition retard set up with the box- probelm was the retard was not mfg by crane and I could not get one - I ended up just putting knock sensors on and ran with different fuel low and high octane to make sure the motor did not detonate -