CamShaft

What engine?

What carb/s?

Anything else done to engine?

With that spec I'd be thinking about torque rather than outright power just sticking with extractors and something like a Kent FR30 cam as a wilder, long duration cam (over 280ish degrees) will suffocate without bigger valves and significant headwork.

If you're looking at this mob:
http://www.aucklandcams.co.nz/cam_listings.php?title=FORD%20CORTINA%202000%20SOHC

I reckon the #341 grind is about right for your spec Max power would be somewhere 5500 - 5800ish rpm. They say its for turbo engine but would suit non-turbo just fine. Assuming 106-112 degrees lobe separation (ask them).

However, if your std valve springs get coil bind due to the extra lift (ask them this too: you might need to get a machine shop to lower the spring seats in the head, or source some Kent heavy duty valve springs from Burtons) or look at their stage 1 or 2 grinds... expect much worse sub-3000rpm performance vs. standard cam but better power up to max power at over 6000rpm.

As you might be starting to realise, there are usually consequences to everything you change in the engine. Thats why the Kent cam kits are a good starting point. You pay a little more up front but then its generally plain sailing after that.