cracked 1g exhaust manifold, leaks???

[91-gsx]

i have a stock 1g exhaust manifold that has a few very fine hairline cracks on it, do these cracks actually leak? i would rather port it because it would save me some money and time. i just need to know if those cracks are going to affect the manifold. i was just going to port the collector because i heard there is no point in porting the runners if the head is not ported as well.
any help will be much appreciated.
later

 

[ISUJakey]

If the cracks aren't currently leaking, they will leak. Ditch the 1G manifold and pick up a 2G manifold as they can be picked up very cheap since so many people think they need tubular manifolds.

 

[oldman]

I have a 2G manifold fully ported, collector and runners, with an EGT tap on the #1 runner, you will have to port match the gasket and turbo inlet. pm me if you want it.