Exhaust Manifold

I never got around to replacing my exhaust manifold with the crack in it.
Somebody on ebay has one for a Midget 1500 that has been "slightly ported
for better breathing. Its like having a Header but keeping the look stock!"

Would this really make a difference?

I am still considering putting in a Weber, but I'm not sure.  I may just
keep the Zenith Stromberg, in which case, I will eventually need a new
Exhaust manifold.

Thanks,
John Gottstein

'75 Midget