Yes, I know how Merc rated the engines. In real world testing though, the 502 MagMPI dynos right at about 400CSHP with the stock cast exhaust and the 500EFI around 510CSHP with headers. So I believe the engine I'm planning for will make close to 100HP more than what I have in the boat now.
So do you think an extra 85-90HP gets me running over 75mph?
It would be nice to here from someone that has a 280 with a 500HP.
I have Stainless Marine manifolds which should flow plenty for a 500HP; they flow not much less than the small CMIs. As for the EFI system, I have an AZ Speed intake, the TB, and fuel injectors from a 500EFI. I also have the Crane/Merc 500EFI roller cam, roller lifters, and roller rockers. The heads I have are from a HP500 carb engine so I'll need to change the valve springs. The wiring harness and MEFI III ECM I also have in stock, but the ECU will need to be remapped. I have a water cooled double electric fuel pump setup that should flow plenty and I have an adjustable fuel regulater. I even have a K&N spark arester/filter for the the system.
What I need is the parts to build a good quality stroker short block out of my Gen VI 454.

I have a 1996 28 with a hp500 all stock with cmi headers. Runs 77-78 all day in the heat. One guy low fuel and the wind on my back 79.5 I run a labbed 28 bravo.

Thanks Kevin, That's what I needed to hear...:drink:
Now I just hope I'll have the $$ after doing our taxes...:eek:

Hey kev is it ever a problem having your boat in heat. Seems it would be a pain in the a$$. Pat go for it i want to see that thing on the ct.,cladios and at block for the boys weekend wish i could have made it but shooting for this year. Take care
-Mike

Hi Mike,
I plan to do Block at least twice this summer; once with the wife and kids and once with the big boyz.
Same with Claudio's, that a great day trip for us.
As for the engine, the next step will be to find a stroker kit for my gen VI 454; most seem to be for gen IV engines.
later all,

Sounds good pat good luck.
-Mike