I have slightly modified my 289 in my 67 coupe. Basically, I put on a performer intake, mallory unilite ignition, holley 650 carb, and a performance cam (I don't remember the specs on it). I notice that sometimes the car doesn't want to idle while in drive... if I accelerate, it wants to stay at higher RPM's even after I release the gas pedal, and I have to quickly tap the gas to bring the RPMs back down. Someone told me this has to do with the torque converter not being able to handle the more powerful engine. is this true? What else could it be?