if this is to go on your Demon, then it would appear your Demon is almost identicle in performance to my Dart. i was stuck on
9.57@139mph for a couple of seasons, the 140+mph was like a brick wall for us to break thru. i was having problems with my 6 pak scoop trying to rip itself off the hood so i went the cowl option, added to that i filled in the front grill to help aid the aerodynamics. with just those 2 changes & the motor untouched, i broke thru the 140 mph bracket to run 142mph & my et dropped almost a whole 10th to 9.48. with a bit of rear end tuning i managed to do a PB of 9.42. so with the engine untouched,i was pretty happy with them changes. how much of an improvement are you looking for?