The 340 T/A was hyd lifters and adjustable rockers and it worked great. Anyone that says it wont work doesn't understand what they are talking about. I have used 273 rockers and hyd lifters several times and they work great checked them once a year and never needed to adjust them.
I didn't see anybody say they wouldn't work. There was a little tiff over mechanical vs. hydraulic lifters. Was the T/A valve train what inspired the "banana grooves"?