Does anybody know what jetting they had in the carb? I have read that they used a modified 850. I know the Merc's had dominators. I have a 950 that I can use. I am thinking about putting a 174 on my current setup. Also what timing, I am guessing no more than 30* with the steel heads and 91-93 octane.
I have what I think is pretty close to a copy of a HP450 454. It was built and installed in the boat when I bought it. I know it has a Crane 268761 cam which I think is like a 500EFI but with a firing order swap. I have CMI's. I believe the compression is 8.5-8.75 with the 088 heads.

They are merc 420s with a 174 blower stock Holley 9022 800 cfm, 26* timing max according to the hawk marine power decal. I have 2 of them in my Excalibur

The carb is just a stock 9022? I read that Hawk modified them to flow more, is that not the case?

lil red,do you run them at 26 total timing?

That's where there at for now, going to put v6 modules in and play with it a bit, mine have over 9:1 comp after they were rebuilt

i know the merc 525sc had 7.5compression ratio,and a total of 35 deg timing.

Yes that is correct, the mercs are also flywheel rated at 525 the hawks prop shaft rated at 525 about 570 flywheel

with 9 to1 compression,and iorn heads,and no innercooler,detonation is lurking its ugly head,be careful buddy.

Do you know what jetting and P/V you have in your carbs?

I'll take one apart today and look for you, thanks mike i'llbe keeping a close eye on it an may go to a colder heat range plug. I've done a lot of tuning and minimal blowing up lol so we should be ok