About the Power Valve. Yes, I've seen the Holly Video but also seen several other online recomendations of selecting a power valve 1 to 2 below the intake vacuum, but yer it is running rich, but since I was trying to correct what appeared to be a lean backfire issue, thought I would try the rich recommendation to see if that cured the problem. It didn't, so I think the problem is with the valve lash adjustment. Engine is on a test stand, so economy isn't yet an issue and I will do a final carb tuning once I get it in the Falcon and out to the track. I've adjusted a lot of hydraulic lifters before, also the hot & messy method, but this engine is proving dificult. Last week I tried that method but when backing off the lifters I couldn't hear them clapping over the loud engine with all the noises from the electric water pump, the electric fuel pump and the mufflers. Maybe rollers cams are quieter; this is my first roller. The engine is on a test stand in my gargage and the Delta 50 Flowmasters are right there at the garage door. Now the other method: The springs on the lifters seem to be very soft giving little resistance when spinning the pushrods, so I'm going to pull the intake manifold so that I can see the lifters during adjustment. Hope to get the that done today.