could the intake be holding my low end down?

Not that I want one(I don’t), but say...... in the past ten years or so(or whenever the OP’s engine was built)..... where would one have sourced the “correct” stock spec replacement 340 “std trans” cam?
This was a one year only thing, right?
‘68?

Which would lead me to wonder....... I wonder what it really has for a cam in it?