Ricky -
You should be fine! Here are some other numbers for you that were posted with ZERO mods - not even filters:
2004 SRT-10 Ram, bone stock: 439.5 RWHP
2005 SRT-10, bone stock: 459.8 RWHP
2004 SRT-10, bone stock: 447.5 RWHP
2003 SRT-10, bone stock: 452.7 RWHP
2005 SRT-10, bone stock: 464.0 RWHP
2003 SRT-10, bone stock: 435.5 RWHP
2003 SRT-10, bone stock: 436.6 RWHP
2004 SRT-10 Ram, bone stock: 437.9 RWHP
2004 SRT-10, bone stock: 420.0 RWHP
2004 SRT-10, bone stock: 436.0 RWHP
While your "magic number" of 440 RWHP is certainly realistic, there is a chance it may end up slightly below it. However that person's suggested target of 400 is WAY off. Also note that the SRT-10 PCM is in learning mode from Day 1, so your driving habits WILL show up on the dyno. "Casual cruisers" (no wide open throttle) will dyno lower. "Drive like you stole it" will put up higher numbers on the dyno almost every time: The computer has set the car up for WOT runs and it responds accordingly on the dyno. Given one of your earlier posts about not being able to go WOT due to traction, your dyno will be interesting.
Now if you had made that bet at 430 RWHP, I think you wouldn't have any worries...