[venom242]

Richer jetting is definitely something to consider. I have heard that these motors were so emissions choked by the factory that they purposely jetted them lean, enough to melt pistons (rumor). If had known about that years ago, I might have rejetted my carb instead of doing my 500 swap.

After my carb was rebuilt by a local shop, my 425 ran like a dog. From that point on, I rebuilt all my own carbs. I highly recommend the Quadrajet book by Doug Roe if you want to know more about them.