hell, the prognosis is not looking good. Thanks for doing that calculation. I did think the specs looked a bit radical, more suited to a torquey 360 I would assume. I have a set of Rhoads lifters, the latest type, V-Pro, I wonder how they would improve things...I have done a lot of reading and seen reviews from many users and they are supposed to work well in cases like this, improving low down torque on engines with bigger cams by reducing the lift at low rpms, but bringing it all back at around 3000-3500rpm. A primitive form of variable timing. Duration is the length of time in degrees the valves stay open, and these lifters won't change the duration but they will reduce the amount that the valves will open in the critical lower ranges. They might be worth a try and these ones need to be used with adjustable rocker gear as well.