Good stuff , but Im just a simple man .....lolNot necessarily more spring pressure on a solid vs hyd roller, if they are similar weight and rpm is the same then no. Most people change hyd rollers in gen 1 SBCs because they won't rpm with the valve weights common in those engines. The LS stuff generally has intake valve weights around 100g +/- 10g so rpm is not a problem. The limit on hyd roller lifters on turbo engines is they will start collapsing the lifter and generally a done deal at 1300 - 1500hp max depending on who's lifter etc. The steel on steel is getting popular with the drag week guys and I put them in a Drag Week engine I built last winter for a guy in TX. Pretty light valve/spring package, cam over .850" lift and plan on turning it 9000rpm. It has hollow stem Ferrea valves, PAC springs/retainers/locks. I had to make some one off spring seats to get the little springs shimmed up to correct height. The springs are tiny but have over 800lbs open pressure. Heads are new Brodix Head Hunter F-Series 15* that are an updated version of the old 15* Edelbrock Victor heads they discontinued several years ago. They flow over 400cfm using the standard Brodix CNC program. There is a lot left in them.