Hola I agree with what Mr. Bell has said about the installing of a six-pak carb set up in your Imperial. Be careful of over-carbing the engine. Take a look at the cfm's of the OEM HP carb's and match it. If you want to have an Imperial that is a notch above the rest, try this. Use MoPar cam number P4286675. This cam gives you more punch than your OEM. The power comes on closer to the normal driving range than the HP cam which starts coming alive towards the upper rpm range. This cam is designed to pull more weight than the other one. Pull the heads and follow the directions with MoPar part number P4120437 to port the heads. Do not take up the ideal of enlarging the diameter of the valves. Just do the porting. If your valves and guides are worn do take care of that issue while there. Look for a dual snorkel air cleaner housing from a HP engine (this unit also came on 383s and 400s ) . Look for a large diameter pulleyed power steering pump. And go for the dual exhaust system that has the "X" built into it ( not the old "H" ) and the other items as Mr. Bell stated. Do not forget the resonators at the rear. Even though I listed the exhaust last, this is the first item to change on your Imperial. The reason is the correct exhaust makes it possible for all the other items to work. If you omit the resonators your car will sound like some hick's pick up truck. Not a cool thing with a prestige car. Rodger & Gabby Colo Spgs '47 De Soto Custom w/Fluid Drive & passenger door mounted swamp cooler '63 Le Baron w/F-Sweep trunk lid & std A/C '66 Le Baron w/dual A/C & reverbed AM/FM