I would go with a bit more duration (260?) but use endurance type roller cam lobes for better life of the parts. So much depends on what you do with the heads, and the cam /carb that it is impossible to give any hp estimates at this point. Figure out how to make the heads flow as much as possible, get a cam to use the flow, max out the compression for the fuel used and get the piston to head clearance down close (.040?) and you should have a winner. It should be easy to get this deal into the tens, but how far depends on a lot of your choices. One thing I am not fond of is the low converter stall. If this is a street strip deal, you have to live with some compromise. But if this is race only, get the stall up above 5,000 rpm, preferably within 1200/1300 rpm of shift point or maybe closer.