Is this upgrade already tapping out the limit of a 496 or is there still some HP to be had? Currently have the Raylar HO600 engine with forged Pistons bored .030 over and dynoed at 660 HP @5400 RPMs. What else could be done to current setup to get it in the low 700's?

Unless you want to pull Ray's beautiful intake off and bolt on a Whipple I think you've maxed out this combo, assuming you have a good exhaust as well as bumped up compression.
Nice numbers by the way...

Yeah, not really wanting to take the intake off for a Whipple. Currently have CMI Sport Tubes and unsure of the compression.

I know there were a couple of different gasket thickness' available to bump up the compression by almost a full point which would help out on bottom end end mid range punch...

Sounds like a new engine build is in order..lol.

Get on the horn with Ray.

Uncle Dave

Yikes!! Not quite ready for that yet......BUT....if I could squeeze a few extra out of it easy I would.....key word is "easy"

At 660hp from what I understand having owned a Raylar 496, there isn't much hp left on the table, unless you start chasing cubic inches or add the Whipple...nothing "easy" or "cheap"..

Mike.

I can say that your Raylar HO600 @660HP is at the reasonable limit of a 496 (8.1L) stock block with special internals at about 510 cubic inches in a +.030" oversize bore. There is no easy addition for the engine at this point and I would suspect any small horsepower increase would only result in a maybe 1/2 mile per hour increase in boat performance and I also suspect there might be more than that result hidden in bottom work, drive setup-x-dim changes or prop science but I don't think any of those will be easy adds.
Raylar does now have the new Raylar - 572-600cubic inch versions availale, built on Merc 496 equipped engines with special blocks, internals and cnc'd upgraded aluminum heads that can produce between 700-800HP normally aspirated. These upgraded 496's would really need an upgraded drive like an Imco SCX, or such to handle the 750-800+ lb/ft. of torque these engines will produce.
Obviously this is not an easy upgrade but its a really good value when you consider what new 700HP plus EFI engines sell for.
Glad your engine is producing the power you were hoping for and I hope you find that easy increase you are looking for.

Best Regards,
Ray @ Raylar