L88 cam in L78?

[Seattle Sam]

I'm planning on pulling the engine out of my '70 L78 Camaro this winter, tearing it down and building it back up to original spec (cc'd heads, 11-1 pistons, balanced and "blueprinted").
I am thinking of installing an L88 spec cam, which has more lift and I believe more duration than the original L72/L78 spec cam, simply because I am a fan of "more power". [img]/ubbthreads/images/graemlins/naughty.gif[/img]

Do you think I will see any power gains from this cam change, since I am running cast iron exhaust manifolds? What if I port-match and extrude-hone the exhaust manifolds, would the engine benefit from it? What about port-matching the intake to the heads?
What if I decide to port the heads, would that make the engine "non-original"? (I know it would not be pure stock anymore, but that's not my question).

On the flip side, what would be hurt by going to the big cam?

I would like this motor to make a healthy amount of power, but I don't want to throw money away on changes that have no benefit..

Please share your thoughts and opinions!

Thanks,
-Sam [img]/ubbthreads/images/graemlins/cool.gif[/img]