It looks like it's down about 60 hp compared to the old combo based on the mph. I'd be surprised if the cam choice did that if nothing else changed.

Speaking directly to the dyno numbers, the manifolds and air cleaner are certainly a percentage of that, along with other normal losses in a vehicle (alternator, power steering, water pump, fan, etc). It also depends if they used SAE or STD correction factors too. STD is optimistic.

If it's not running out of fuel on the big end it would be worth trying to jet it up and also adjust timing to see if it will respond to either of those, definitely check the plugs and compare that to what the wideband is reading.

Also worth checking to see if the cam is losing a lobe, like csk suggested. I was down a lobe in my '68 Charger when I pulled it apart and it ran fine, I had no idea until I got the old cam out that it was wiped.