A cam won't give you high power. A cam will HELP you get high power, in conjunction with a number of other items.

An engine makes power by burning fuel. The more fuel that you can efficiently burn, the more power it makes. The cam will assist in improving VOLUMETRIC efficiency, in conjunction with an induction system that can supply more air & fuel, & an exhaust that is able to remove much larger volumes of exhaust gas.

To install a hot cam in an A series engine is a major job involving engine removal [if your smart], so the best bet is to improve volumetric efficiency by other well tried means.

Go with an exhaust upgrade & a Weber downdraught carb with an adapter on a standard manifold. When correctly tuned it will run as sweet as you like & be a lot peppier too, but big cams in standard engines is just a lot of work & a fair old spend for nothing but grief.