I had them installed at university hospital in cleveland oh a couple years ago. My doctor of 35 years told me I was breathing better! Any improvement is a blessing. It's was the least intrusive operation/procedure of both choices. 5 days in hospital. Would I do it again yes. Nice El Camino. My 1966 c10 can't help but make you smile! Especially when getting rubber from 2nd gear. C YA

Hello Kevin
I was tested for the zephyr valves but didn’t qualify due to collateral ventilation but if u r on Facebook there’s a group search Zephyr Valves Group and there r a lot of stories good experiences and bad ones too. That’s where I got my information. Sorry I hope this helps u.
Dawn

Thanks Rick, I'm looking into it, I also like older trucks