Pratt's heads were bigger (305's or 315's as he was anticipating 540's down the road), cam was bigger, and ran a dart single plane intake. Ran great until he hydrolocked/punched a hole a cylinder (bad exhaust flapper coming off plane). That block was sleeved and they have since been upgraded to 489's with Eagle rotating assembly. The original stock 7.4L (Gen 6) blocks/rotating assembly held up fine but he limited the RPM to 5,200 WOT.

The blocks are GEN V 4-bolt mains and yes using the stock cast crank. Running the standard bravo 1 outdrive, do any of you guys run engine rpm above 5000?

I would prop it to run 5000 rpms for your average boating conditions and then under ideal conditions with a light load, it would prob run up to 5200-5300rpms.
I ran my old 454mag with upgraded cam and roller rockers to 5450rpms with no issues. My 525SC ran 5300rpms at WOT. My 502mpi's run up to 5100rpm in ideal conditions.

That will be the plan. Thanks

Thanks for your info and offer. The set of 26" you have, are they extra? IF 26" actually worked on my boat, would you sell yours? Thanks again

No, not really extra. I have a set of stock 26's, a set of Mercury labbed 28's and stock 30's if I ever install my Whipples. I'm still tuning and experimenting with drive spacers and don't know what I like yet. lol Just have them to trial so you don't end up buying what you don't need.

Sounds good. I didn't think so but if you don't ask you don't know. I was just over to Mercury's slip calculator trying to figure out where I might be and really if I'm not able to run my current 24" to 5500 rpm or the 26" pitch to 5000 rpm I am afraid I am going to be a little disappointed. That puts me right at 74 mph with 10% slip. I don't know if that is a realistic slip number either. Really not sure what to expect from an approx 300hp gain. In my mind that's quite a bit. Almost like adding a 3rd engine. I am going to look around for another shop with a dyno. I feel as though there might be a few extra hp in there and I really want the graph. I do know that currently the air flow ratio is running in the low to mid 14's. He said with my compression ratio that that would be fine. I was thinking it supposed to be around 12.8-13.5 ish. In the real world maybe this is 1 hp. I don't know. I would like it to run a little "fatter". Thanks again for your offer with the propellers. I may take you up on that this spring. Are these your primary props or are the 28's?

You are 14s at what rpm/load? If WOT don't run it till you fatten it up. Hopefully you didn't damage anything.

I don't know the "load" applied I can only tell you it was a run on the dyno. Not sure that answers your question or not. It was back firing a little at lower rpm and would the carb would catch fire and shut down. Some of that I think was the timing because he advanced it a couple degrees and it stopped. The more I talk about this the more I don't feel well. We ran from 3000 to 6000 probably 7 times or so. No smoke from anywhere and it still sounded good after all was done. I realize that last statement is not scientific but no unusual noises. Going into this I was thinking that the 800 cfm dbl pumper Quick Fuel carb was going to be a little big.

I don't want to get too deep in the woods here but he did pull a couple plugs after a couple pulls and they looked fine.