If you're concerned with clearance on the intake manifold and heads that need machining and work, HOT ROD just did a top end rebuild (albeit with an SBC) and they found out that after piecing together parts and making everything work (it didn't), you can save money and time by going with an aftermarket head/intake set that includes all the hardware, gaskets, valvetrain, etc and is guaranteed to be compatible.
Food for thought.