Right Now for GM engines Hydraulic Flat Tappet Cams I can only Recommend Iskenderien 202HY lifters in ChevroletV8 Pontiac V8, and Oldsmobile V8.
202HY Isky is what's in my 1976 Pontiac 455 now, bought directly from Isky in Los Angelous California late 2019, recall box lifters made November 2019.
About 1 week prior to my order.
Have 1 more set for the Olds 425 V8, bought 2012.
1 set of Isky 202H Solid Flat tappet lifters for the TA.
Really Low budget is over.
I sunk a small fortune into the 1976 455 to get it where it is Reliable Powerful.