is it worth going to bigger valves in the stock heads and porting them or just sell these and purchase another set?

 

On a back to back (within 10 minutes of eachother) flowbench test of my home ported set of heads, the Manley RaceFlo 2.00" intake valve outflowed the stock intake valve by 3 or 4 cfm at peak and almost that over the entire lift range. However, on the exhaust side, the stock valve flowed 4 or 5 cfm better than the Manley RaceFlo 1.56" valve. This was after I worked the combustion chambers some too, and I think the bigger exhaust valve was shrouding a little bit.

 

no doubt 2.02/1.60 is the only way to go. you will need new seats pressed in but i got real good #'s from mine i used the race flo's and my ported stockers beat both edelbrook and trickflow heads on the bench

 

Ported head vs as cast just means the heads were ported to flow a lot of air.
take a set of old 202 fuelie heads and flow them compared to a stock LT1 head and oh my the 1.94s flow like hell in comparison so they must be the ticket right?

There are going to be cases where bigger valves can work better but most people don't give stock and stock sized anywhere near enough credit. This is even ignoring the fact a flowbench is a tool not an absolute measure of what a head can do on an engine.