This is the first time that I have commented on this subject and it's an idea that our driver Roger "Radar" Lechtenberg (Nitro Madness AA/FA) mentioned to me several months ago regarding oil downs....he works on cylinder heads for a living so he gets to fix a lot of broken engines....Radar said "Just limit the valve lift and they would solve 90% of the oil downs and Funny car body launches".
It's very easy to police this rule and check total valve lift without taking the engine apart....I don't think cylinder heads and/or the valve train were ever designed to handle the valve lift the current top fuel teams are using.....and I'm not sure what the total lift number is, but most of the failures begin with a dropped valve....maybe limit them to .650" or .700"?.....just a random number and if NHRA chose to adopt this rule I'm sure they could come up with something reasonable....this rule might slow the cars a little but with forced induction the crew chiefs will always find a way to make it up....
Just a thought....