Id be more worried about detonation. What octane fuel?

One issue I had , was the one holley iac harness i had, was wired for a chrysler iac. Well, plugging that into the LSX style IAC I had, everything seemed fine. Problem was , the ecu was commanding iac, and giving feedback, but the iac pintle was simply not doing anything. I couldnt figure out why the hell i was getting significant rpm drop when putting in gear. Chased my tail on that for a minute. It was a matter of swapping two pins to fix.

I run 110
engine temp is 125, oil temp on full boost and 5000-6000rpm is 235, this block also oil squirters under the pistons.

yes I can with my ecm. No need to though

Your effective compression ratio is 21.5:1
Good luck with that in a marine endurance motor .

if it ended like that I’d say thanks, but effective compression isn’t the end. Cam timing, lift and duration also affect that number. I’m pretty sure my builders know a bunch more than anyone here. We did a tear down in January all was perfect. 35 hours on it and in perfect condition.


That’s Jim Shofner, owner of Arizona Speed and Marine. He actually designed and built that intake and continues to manufacture all blue top motor intakes. He is currently designing a wiring harness that will convert any Holley ecm to work with just about any mercruiser engine.

Yet youre here seeking advice.....


Thats a bold statement, theres quite a few really sharp guys (and builders) on this thread offering help. Not the first "1400hp" procharged build we seen here over the years.

I think he is out west running that setup at elevation.

Another know it all ... We`re all idiots cause the 100 year old tuner knows more than anyone of us.
At $9/gallon I bet the thing don`t get run for extended periods so maybe that`s what`s saving your a$$.
Never once heard a good thing about Speed and Marine, quite the opposite.
Good luck, ask your builder any questions from now on .

I didn't come here to diss any of you or even listen to you guys call out a "100 year old tuner" etc. thanks for your input. check yourself or bring your bada$$ boat to Havasu or the Lake Powell Challenge and lets square up. Id rather ask you guys here to engage in some chat about idle tuning and learn than anything else. Good luck fellas.

I've got no dog in your tuning fight, but did notice this PSI mentioned in your other thread awhile back.
Never heard of them.
Do you know, is this who he's using for base engines or blocks? https://psiengines.com/

Otherwise, I missed it in the 1st picture with the crossover in place.
Anyone else seen big block heads with water ports for a crossover?
Answered my own question. A Gen 7 thing. Never knew.