depends on how much you're expecting from it, have you bought the ford falcon six cylinder performance handbook yet? if you haven't, I highly recommend it, but speaking from my own experience, you'd be lucky to get 10 more ponies out of it. try looking at your exhaust system first because the original cast-iron log manifold is easily the worst power drain on the thing.
Hi, you should probably find a three one's manifold adapter, but this needs some work to modify the factory integral intake manifold. Other wise you are dealing with the funnel effect. You can only get so much through that single hole.