From personal experience;I build a 302 about 8 years ago.302 head with Chevy V8 valves,Venolia 9.25 pistons,cam is 215 degrees duration at .050 lift,single 4 barrel carb,home made short tube header. My 37 Chevy truck with this engine was driven by many inline guys over the years and will out pull a stock 270- 302 from 1200 rpm on up. It has exception throttle response and fuel mileage.Any engine's performance is the tuning of the various parts.I sold the truck and 60,000 miles later still runs well.
A 270 H or 302 head by todays standards is pretty tame.Think about it,GM used these engines for the heavy duty truck service,they were not performance engines originally.
A small port head will do fine,no need to buy a overpriced 270H head for a mild street 270 engine.
