460 intake manifold
hi i have a 1987 motorhome with a 460 65000 miles on it. a few years ago i had the motor removed to repair broken exhaust manifold bolts. i asked the company doing the job if they could give me more power and better on fuel so they removed and bypassed all the pollution items. now on the intake manifold the plate they used to cover up a exhaust port of some type on the passenger side of the intake now has a rust hole and now i get fumes inside the cab i broke the bolts off trying to remove this plate. should i remove the manifold and drill out the broken bolts or should i replace the intake and with what type. also should i go smaller jetting on the holley carb because when i climb steep hills my friends that follow me they say lots of black smelly fuel is coming out of my tail pipe. thank you all for reading this and your possible solutions.