That's very nice, and those are very nice numbers. But as far as adding a bigger cam to wake it up, I think that for a street car engine, your engine is already awakened about as much as it could be without getting into race gas territory and/or taking it off the street and onto the trailer due to driveability issues.
660 HP is plenty for a naturally aspirated 489 engine on pump gas being used in a street driven combo. Mark Jones' 496 engines are pretty stout too and are both affordable and make great power for engines with great street manners.
As far as making 750-800 HP with a 496 CID engine naturally aspirated on pump gas, I don't see that happening without using a cam that's so big that you can kiss any degree of street manners good-bye, and you would also be getting into race gas territory.
Sure, you'll get guys with 496/505 cid pump gas engines who are using cams in the 270 dur@.050
range or greater, along with 5,000 RPM stall speeds and 4.10/4.11 rear gears, who will try and tell you that their car is a "street" car, but ask them if they ever drive it for an hour at a time or longer. Ask them how their rear gear ratio is on the highway. Ask them when the last time was that there were in a traffic jam with it. Or exactly how many miles they put on it per week during the warm months of the year. That's when you either get tall tales, all out lies when they're in denial about these things, or they get quiet.
I guess the bottom line is that you really have to decide for yourself what you mean by a "street" car, and how exactly you intend to use it, and more specifically, how often you plan on using it on the street.