Being very general here... The Demon will make more power. How much more, and whether or not it's $$ worth it, is up to you and your tuning skills. My experience with Demons is limited, but based on that, I'll keep it limited. I would prefer using a Holley Avenger, those I know dont come factory with crud left over from machining in the metering blocks and bowls. I've hear BG took care of that, but I also found them (once "fixed) to be very finicky. In almost all cases they need work Out of the box to run their best. That's not to say they cant run..Just you have to keep messing with them, and when you're done, and the weather changes, you're back to square one. (so good at being adjusted, that they will need constant adjustment to match conditions..EFI does all that for you...) My main point was, the longer stroke will create a much stronger signal at the boosters and under the plates. So, a larger carb will not act at all like over carbing a stock stroke engine. In fact, in many instances, the air bleeds and passages in the larger carbs are sized properly for an engine moving the air the 416/408 can. So idle can be better, and power be much better. I dont think changing the cam right now makes sense. You're leaving some on the table power-wise, and until it's all set up right, you dont know what you're missing, and you have to go all thru the same steps anyway. Do it now, see if it keeps you smiling. If it doesnt, and iot cant be gotten any better by you or a pro, then change the cam. I agree with Rumble tho, a change that large in cams make effect other parts of the driveline.