I have driven my 32Pacearrow 460 now....just put new manifolds on it and a true dual exhaust with big walker muffs...pulled hills near by at least 10 miles/hr faster, and in the 90 degree heat a lot less temp on the gauge ....PLUS I installed two fresh air vents 4inch from the front to on top of the manifolds.... cut two 4 inch holes above my headlights , used 8' aluminum dryer vent hose , routed it around and pointed it to my manifolds.Even climbing at 45 there is now normal air in my engine compartment.....and air at 45 MPH force.....