I got them when they first came out, and they're still working fine.

'69 b body, I tried two sets of headers and two exhaust (among other things) in the pursuit of speed.

For spark plug socket clearance....2 small dings required with hooker competition b body, none required with 2" super competition b body.

Before bolting in a car, put the heads on a bench, bolt the header on and make whatever adjustments you need to make to change
spark plugs. Or do it on an engine stand.