I run an Offy manifold on my 292 with a 625 cfm Carter AFB (same as an Edelbrock 600 cfm, essentially.) I've had it there for a little over a year. I love it. Great setup. People told me I'd lose...well...just about everything...torque, driveability, high end power, low end power, mileage..but none of that's turned out to be the case. It starts right up (gotta love the electric choke) and has very little of the one-barrel coldbloodedness that the Monojet had. It's very driveable, with no loss if low end power. I think I'll keep it. Oh...mid and high range power are great, too. You can sure hear it when the secondaries kick in.
Exhaust: I run Hedman split Hedders with Cherry Bomb glass packs. Yeah...just like the 50s. And it sounds like it. (I had a guy tell his young helper, "now THAT'S the way hot rods sounded when I was your age!) I have the exhaust exiting in front of the rear wheels on opposite sides of the truck. This wasn't exactly what I wanted, but it's what the muffler guy put on...so I left it that way. But I love the sound. Yeah, it raps and crackles as it winds up and it snaps and pops when I back off the gas, but that sound fits the personality of this truck perfectly.
If I wanted a low, smooth sound, I'd use a single 2.5 or 3" exhaust pipe with a turbo muffler and not keep the 2 sides split. The quieter I wanted it, the larger muffler I'd use.
The X pipe (I have one on the 406 V8 setup in my 80 El Camino) works well for a 90 degree motor, but doesn't do the same thing on a 120 degree (I6) motor...it just kills the split exhaust sound.
I'm happy with the way my truck is set up...but it wouldn't be the right setup for everyone.
