I just purchased my first classic Mopar, a 1967 Coronet 440 with 87k miles, a stock 383, 4bbl carb, 3 speed 727 torqueflite, and a 8 3/4 rear end. This was originally a 2bbl so I believe it was originally rated at 280hp. However, right now it feels more like 150hp. The first gear acceleration is "fine", but it feels the car starts to become sluggish after 30mph and acceleration decreases. I'm not expecting it to perform like a modern car but I think this motor can do better. Last night I checked the numbers and the intake is a Chrysler unit from a 440, with number 3830949. Edit: People have suggested below this is from a 400, not a 440. The carb is a Rochester Quadrajet 17086046. This is a GM carb that came on 4.3l trucks. https://www.carburetion.com/CarbNumber.asp?Number=17086046 I'm not an expert here but I think this intake and carb combo is not the most efficient. Are there any power/torque gains to be had with a different carb? I know it's a stock, tired engine with a 3 speed but I'm sure it can do better. Any suggestions?