These any good

Looks similar to the 440 source head, although I've heard that those are ok, I know nothing about these.

For a while, there was a chinese company doing knock off versions of RPM Air Gap manifolds. They looked nearly identical, visually, without the Edelbrock name, but when a magazine flow benched it, the #7 runner on 3 of the manifolds they checked were insanely short in flow.

Anymore, even with good companies, you have to be a little crazy with your own quality control and more now than ever, you really do get what you pay for, because of every company pricepointing the hell out of everything produced, packed and freighted to retail. Quality control seems to be the first place an outsourced, internal company shrink management contractor hits.