what is a good intake to run on a carb. gen 6 502 with a mild camshaft and holley 800 carb?

RPM air gap works very well.....or for a little higher RPM the dart

I've been really happy with the weiand stealth. Its good from idle to 6800 which is perfect for a hi-perfromance marine engine. IMO no need to use a single plane, you give up too much low end, lower mid range and throttle response for a slight edge on the very, very top.

Merlin dual plane.

That intake was on my radar but I don't think they make it any longer.

Just got done dynoing a Edel RPM, Stealth and Dart on a 496 build. Surprisingly to me, the RPM did the best having 30 # TQ over both the stealth and Dart up until 5000. The stealh and the Dart were nearly identical until 5300, at which time the single plane started makin more power. Usable power to the boat, RPM was clearly the best. I loved my Dart for years......but I have the black merc paint out now painting the RPM.

AirGap RPM's are nice for a motor like yours. They work great !!