Just finished making 533HP on a stock block 496HO with new heads, new intake manifold and cam! This was done with a stock Merc ECM! Thought this might get some 496 owners excited!
Raylar

Nice!!!!!!!!!!

so , will that affect the cooling system?? i take it wouldn't if you achived these #'s with no ecm mods?

I think you should try to sell Mercury on installing your products at the factory. Think they might go for it?

Is there enough room in say a Fountain or Formula to get a cam in without pulling the engine?

What was the cost of the upgrades?

Cost of the upgrades are about $5800 plus someones labor. Some guys have been changing cams without pulling motors by installing a plastic inspection plate behind seats on bulkhead. As for convincing Merc to install these parts at the factory, that would be nice, but that's up to Mercury. This is still a lot less expensive way to go rather than spending 20 to 25k more on a HP525EFI. As for cooling system, we have not seen any problems as long as the raw water pump is in good shape. Remember some guys have been running superchargers on these motore at over 600HP without overheating issues. I know there will be a lot of 496 owners making this upgrade real soon. Make reliable affordable power and they will come!
Raylar

Raylar,
Is that 533hp with only the changes you listed, more to the point - is this with stock exhaust?
Also, what is the torque before/after your upgrade.

Thanks,
Rick

Do you have the Tq and Hp curves?

I saw the your webpage info on your heads, can you run 89 octane at the 10.1 to 1.
would this same setup work on a 502 EFI 98 gen 6 ?
thanks Bill

That's it. Keep tempting me to pass on purchasing extended warranties. Keep it up, PUNKS!! Last weekend I caught myself looking to see if I could slip a cam in. DAMNET!

Did a little poking around on the website. Does the plastic engine cover go back on after your intake manifold? What clearance do you add or subract to the top of the 496HO with your intake manifold? Do any accessories have to be permanently moved to accomodate the manifold install and/or the heads? What is the required octane to get the performance you are experiencing?