This stuff pertains to N/A engines as well.

I think that "only 7-8 lbs boost" may have something to do with it. This isn't the motor sitting in Tony's shop is it?

Actually I think it's worse with a N/A motor and some compression.

Not hard to figure out really, the stock timing curve on most mercuruiser efi programs goes to 35 degrees or so at wot when base timing is set at 8 properly, too much timing for boost really,they use a mefi2 or 3, I went to a mefi 4 that has a timing boost retard table, I pull mine down to 32/33 under boost using a -2, -2.5, -3 on the table. Procharger tells you to set base timing at zero or 4 degrees , cant remember its been so long since I paid any attention to there half ass instructions, but when you do this bandaid they want you to do the boat will barely idle and load up at part throttle so first thing everyone does it turn it back up. My 540 detonated on dyno even at 7 or 8 psi of boost when we tried 2 more degrees of timing past 33 total and its 8.2-1, a stock 8.8-1 iron headed motor will be even worse, prob had too much timing and or not enough fuel, fwiw, Smitty

Artic What fuel ratio range have you found to be ok with the procharger under some boost WOT 11:1 give or take?

yes, everyone thinks cuz its NA , this stuff doesnt happen. A NA engine can have as much, if not more PEAK cylinder pressures. Many have a hard time understanding this. Kind of like if you compared say an 8.5:1 blown engine with 7lbs of boost. Lets say that gives an effective compression ratio of 12.5:1, but can run on 93 gas all day, and maybe an NA, with 12.5:1, will detonate sooner on the same octane. Supercharging doesn't really increase the peak cylinder pressure, it increases the pressures from BDC to TDC more so, from better cyl filling. As the power per cubic inch increases, the chit hits the fan alot sooner, whether NA, or blown. An engine making .7HP per ci, is gonna be alot more tolerant than an engine making 2hp per ci.

7-8 lbs boost with the stock map was a grenade waiting on pin removal,stab gas and BOOM.

also increases cyl pressure from whatever advance before tdc ignition starts until the exhaust valve starts to open due to the xtra air-fuel charge from the supercharger or the xtra squeeze from higher compression ratio on the n/a engine.

some boost,,what do you mean by that?
I tuned some 540's w/ afr 335's and 8.5-1 comp ratio in a 382 fastech w/ arneson's,0-4lbs of boost is in the 12.2/3 range w/ 33° of timing,5-7lbs gets 11.6/8 w/ timing at 32° and 8-10lbs gets 11.2-11.4 w/ 31° timing.boats run a best so far to 112mph in the ocean.btw,I set up his cylinder heads.
video of us after some lower load cell fuel trimming
https://youtube.com/watch?v=OhwGR64_Ghw

That's how you make it rain!