Hi Cliff, back in 1991 I got one chance to shoot photos on the starting line at Pomona, thanks to the late Leslie Lovett of ND. Les gave me exact instructions including where to rent a super long telephoto lens, how to focus, where to stand, etc. Anyway, I tell this story cause the sheer noise, vibration and yes, HEAT was shocking to say the least. I've often told many that it felt like you miraculously survived a major disaster after each fuel run! That race yielded the reference material for my first drag racing lithograph, Chuck Etchells' '90 Trans Am FC, the same one that won the Summernationals.
As far as today's FCs Jimmy Prock of Force's team discovered if they angled the headers back a few degrees the added thrust created free horsepower. NHRA eventually limited how far they could be angled and I think they have been more restrictive in recent years. Others here would know better than I.