Hello all, Question of the day! I have a 69 mach one with the original 351 W 2 barrel Im planning on having the engine rebuilt this coming winter with some performance upgrades and Im curious if I end up needing to go with a 4 barrel carb. Which I already have a factory intake for, will I need to change out the heads to heads from a 4 barrel engine or are heads from a 2 barrel engine compatible? Im looking to bring out a little more horsepower without doing anything drastic like an engine swap or such, as Im the second owner of this numbers matching beauty and just want to give her a little boost. So if any of you Gearheads can give me any input I would be grateful, Thanks Gang!