have pair of carburetor 540's with 28pitch Bravo 4 blades turning 4600 R's is this lugging? or should I drop down in pitch for better performance? My cruise speed is great 50 mph at 3200

Depends on a few factors.
1) what cams (rpm range)
2) what drives and ratio (1.5:1 or 1.36:1)

I quick thought would be you have 600-800rpm left. I'd say if all adds up a 4 blade 24-25 would be a perfect set-up and easier on the drives.

Unless they have very small cams, they should most likely be spun at 5000+ rpms. It really depends on what the engine internals are.

"cruise" speed will always be faster with more pitch. However, the load on the engine, with the 28 pitch props at 3200, is much higher, than if it had say, some 25 pitch props at 3200.

Sounds overpropped to me. Like these guys said, it depends on your engine package. IF your engine makes peak torque at 4600, and peak HP at 5500, running it at 4600 wide open, is not good in my opinion.

We also don't know what hull he's pushing.....

Exactly. And doubt you'd have 540 builds with 218 duration or less. Even stock 454 mag I never even would run under 5k. Just don't feel right. But yes your lugging your engines and working them hard. Are you trimming it out well. Only time I've seen that rpm in a boat was in 5/6 footers when drives and tabs are mostly if not all the way tucked in. Plus 1 for 5,500. Drop down a couple of prop sizes and you will pick up mid range and top end also. It will act like a completely different boat.