from what research I have done the heads don't need porting and polishing for most mild to moderate performance work. The ports are already too big! Take a look at these and then do some research.http://www.mpgheads.com/PortPlate/PortPlateDetail.htm
I have been told the intake plates are hard to get to seal and that they are not as helpful as the exhaust plates. If you want to do something to the intake side, these look like the ticket and are what I will likely be using on my build http://www.pricemotorsport.com/html/body_ins-351c_4v.html
There are also some exhaust plates made by Holstrom.
and a more expensive option http://www.pricemotorsport.com/html/body_ep-23___high_port_exhaust_plat.html
By now you are probably adding up the costs and thinking I should just get some Aussie 3V heads and have them built! That is a good option too, but aluminum has it's own disadvantages.
That manifold looks good, but the basic operating range is pretty broad and I would expect it to lose some low end torque in order to get the top end numbers. Decide on the operating range you want to use and try and match components to work together. While the Cleveland will turn 6800 RPMs there are few cams that are streetable that have a power band over 6300 RPM.
Decide on what you want and start with the cam to build your engine around. Cams need certain rear end ratios to operate best as well as the right stall speed converter or a 4 speed. Hydraulic cams are somewhat limited at the top end and you can get more RPM's out of solid flat tappet cams or solid roller cams, but the solid rollers and matching lifters get a little pricey.
Solid lifter cams tend to need valve adjustment fairly often (every 5-6000 miles a bit more if you are lucky) but you can slightly alter valve lash to change performance characteristics a bit.
I'm still searching for a cam I like. There are lots of makers that will custom grind a cam-I am not going this route as the cam designers are probably more in tune with what works than I could ever be.