- charlieRobinson wrote:
wondering if 20WHP gain is a good expectation from those who have installed upgraded heads.
I would say minimum 20HP. Air flow is everything when it comes to power production. Of course everything depends on whether the head porter knows what he is doing.
I picked up between 80 and 100 HP when I replaced my iron heads with ported aluminum heads. Went from low 13's to low 12's at the track.
98 Riviera SC3800 All stock except gutted air box.
1970 Buick GS455 Stage1, TSP built 470BBB, 602HP/589TQ
Best MPH, 116.06 MPH, Best ET, 11.54