The Indy heads are a good choice, but there are a lot of factors to consider with any head you purchase. Hughes knows their MOPAR, as does Indy, so both recommendations are excellent. With the current thinking regarding cylinder heads, low compression ratios, and attendant low cylinder pressures, are still the norm. Aluminum heads are not as thermally efficient as iron, and require more compression to make comparable power. Pump-grade premium gasoline can be successfully run in an engine with iron heads, with a compression ratio as high as 10.75:1. Use at least an 11:1 compression ratio in your engine, with the camshaft you have chosen, and aluminum heads. A stock-block 318 made over 500hp at Indianapolis in the late '60s, with exotic heads created by Westlake and Dan Gurney. The block is not as much of a hindrance to higher power levels as the airflow capability of the cylinder heads. If money is not a major consideration, then go for the best flow you can get, and match the rest of your valvetrain and compression ratio to the flow capabilities of the heads.
