Don't remember a Chinook doing 190 knots, but, what's Vne amongst friends anyway.
Yes, War Zone D. 334th at Phu Loi I remember. Geronimos of course. Worked in team covering INFANT as the low bird finding stuff six months late '70 - '71 FOB. Nothing like a little night roam-about to lose some weight - little that I had.
The UH1Ms did have the -13 engine and of course the thread subject 540 rotor system. I preferred the four crewmembers, 8 eyes, bungee 60s, and minis and rockets of the UH1C - just felt more secure I guess. Nicer to have four guys on the ground when being forced down too. Breaking over the target was a really big no-no for very obvious reasons. We never did anything the same, ever. Always different tempo, direction, height, angle, lights, etc. Our theory was it kept the little people with big guns on the ground guessing and hesitating. Didn't always work though.
Favorite A/C = XV15 - definitely not a 540 rotor system though. In that interest it would be curious to see a 412/212 fitted with a short 214ST type rotor - might do 150IAS? Getting experimental here.