A lot of mods that work on the Charger will do the same for the Challenger. I have swapped heads, cam and exhaust on my 2006 Charger Daytona (5.7) to increase my rear wheel hp to a dyno'd 384! 1/4 mile times in 12.8ish but with converter can get lower. A gentleman with the same car as me has clicked off 12.2 in the qtr, slightly different mods (different cam,long tube headers, torque converter, CMR tune). We are talking more power than a stock SRT Challenger.
Some very good people over at
www.challengerforumz.com with info on the 3.5, 5.7 and 6.1 upgrades. If you have a new Challenger you owe it to yourself to at least check them out.
If you want some tips or pointers I would be happy to help out.
The Diablo Predator would be THE TUNER to get for the Challenger, IMO.
Right now I can get a 6.1 based 392 stroker for $6k. Man that is a deal but it woul dblow my 73 Challenger resto budget for the winter, something I don't want to do. The 392 stroker was dynoed at 480 rwhp though
