[undy]

Once you get things sorted out try to get your AFR around 12.5 to 13.0 at WOT. Actually, for a semi-docile, stock iron head 390 240 rwhp is about what I'd expect it to be. Figuring a 20% drivetrain loss, that's 300 hp. Torque is the FE's forte' anyway (dump truck motor, but I luv 'em). The standard stock (non-CJ) iron FE heads flow terribly. I honestly don't think you'll pick up a ton of HP/TQ with new mufflers. Your engine's capability just isn't there to use it. With the low profile air cleaners that we're forced to run I always have the choke horns milled off. They're just too restrictive with the air cleaner top nearly laying on top of them. I think a 650 DP would be more appropriate.

I think there's three things fighting you here.. cam (you didn't mention specs so I'm assuming), heads (a set of Eboks would be nice) and last but not least.. exhaust. I don't think exhaust will be as much of an issue until you step on the motor somewhat though.

Actually, pull the sidepipes at the header flange/slip joints and make another run. That'll tell you if bigger bore pipes will help you out.. It might save you some $$ and guess work. jus' my thoughts.

Dave