I have more of a surge at idle and recovery with my ramjet (in my 2000 tahoe tow rig) and its pretty much always been there, I've just grown use to it. The one thing I'd say is check over the manifold bolts and the 8 bolts that torque the plenum to the base the base to the heads wasn't torqued right from the factory or within the first few run cycles loosened so those had to be retorqued, and the bolts from teh plenum into the base manifold were always slightly leaky.
You really have me wondering if throwing an aftermarket efi system on the motor would clean it up a bit, I'm on the first generation with no O2 sensor (came out a month after I ordered it and wasn't upgradeable just replaceable) The truck never performed the way I wanted on the track, I just attributed it to all the accessories, and a truck driveline's parasitic loss (4l80, 14 bolt semi floater etc) sucking up the power, darn thing only dyno'd around 350-370 rwhp. but hell its been alive for 27K miles now at least 30-40 bottles worth of 200 shots, and towing 8K lbs. Love the motor and tranny more than teh truck so I'm keeping them after the tahoe and finding a lightweight donor/bracket car so maybe I can keep it efi and get the thoughts of carbing it to get it more effective outta my head
but hell if it can lift the front wheel of a 5850 lb truck with a 2500 stall on motor I can only imagine in a 'normal' weight car.