302 performance

I'm planning to give my Merc Monarch some better performance. I want Edelbrok Performer RPM cam (1.500-6500rpm), Performer RPM intake, some 650cfm carb (Holley, probably), Flowtech headers and Flowmaster 40 series mufflers. I also want to get the heads lowered for higher compression.
What kinda horsepower do you think I get?

If you want to utilize all of the cam you may want to get the heads rebuilt. If you are running stock heads it would be a good idea. You could take it to a machine shop and have them take the heads apart and clean them. You could also ask them about buying and installing some performance parts. Such as valve springs, valves, and have them look at all the problem areas to see if they need to be fixed/replaced. The price for all this varies so call around or get some input on which local machine shop is best or more advanced with automobiles.

Yeah it would be a good idea too get the heads P&P with the cam and carb.