PTV = Piston to Valve clearance. Something that's not (actually rarely)always a necessity in checking when working with stock cams and pistons, unless you're swapping heads onto an E6SE headed long block that's got true flat top pistons with no valve reliefs. Just the head swap alone in this case moves the valves a full 1/8th inch closer to the piston tops. And even closer if swapping cams too. PTV clearance isn't just an issue with total valve lift, but also with the actual valve timing events and duration of the lobe lift. ..........................................................Thermo bumps = that's short for the "Thermactor" bumps that are found in the port roof of small block Ford heads. There's a hole drilled into the center of these bumps that's how the fresh air is pumped into the exhaust stream by the smog pump and it's plumbing. Someone at Ford (way back when) decided that the fresh air needed to be introduced into the center of the exhaust flow, hence the reason for the bump intruding into the port. Someone else in the Ford Racing Program suggests that removing these bumps is a cheap way to free up HP by improving the flow in the port.
If you go with the E7TE's don't forget to fill the thermactor holes in either ends of the cylinder heads, there are kits you can buy, or just find the right sized set screws at the hardware store. There should be a thread or 2 about it already.
