I have a huge collection of tapes and a long memory...
If we're talking about tag matches (with either Martel or Pillman), he had very good to great matches with a boatload of teams:
Midnight Express, Samoan Swat Team (believe it or not! I have a damn good match on tape from a house show in 1990), the Freebirds (as good as it gets with these clowns anyway), the Dream Team, the Islanders, etc.
Granted, I'm not saying he's the most talented man in these matches; he did step up and carry his end with damn goiod performances.
As for singles matches, he's had damn good ones with:
Pillman, Eaton (trust me! I have about half a dozen of their matches on tape and most of them are damn good), Lex Luger, Scotty Flamingo (Raven), Terry Taylor, etc.
Again, some of these guys are great workers and were more responsible for the match being so good (with the exception of Luger). But Zenk busted his ass in a lot of these matches.
No, I never saw a particularly good match with Zenk vs. Arn. Then again, I think Arn is vastly overrated as asingles wrestler.
None of the above are the less talented heels I was talking about. I'll get into that later.
I'm not saying Zenk was a great worker but let's try not to shit all over him.