First 408 build and going with indy heads

All the more reason to ditch the squish lifters. IMHO to use a hydraulic lifter in your application is a crime. A SFT will make more power, RPM higher and live just as long as a HFT without the HFT limitations.

I say PISS on hydraulic lifters. If that is what Hughes is telling you, they would be wrong IMHO.
Hydraulic cam was my preference with what I had ran in my 360 set up. Ran same cam and lifters for 17 years never adjusting them and never any problems with great power. I will get with them and upgrade to solid before install