I have a set of Non P.I heads make offer
Don't relegate those non-PI heads to bass-boat-anchor duty just yet. The ever-inquisitive minds at Livernois Motorsports have discovered that those much-maligned castings, as fitted to '96-'98 GTs, weren't quite the restrictive corks we all thought them to be. With a little touch-up work-and the proper sup-porting cast-they can support big power. More surprisingly, it turns out that even stock non-PI heads can do a decent job if you feed 'em properly.
You'll no doubt remember that the wheezy first-generation modulars could manage only 215 factory-rated horsepower, compared with the 260 ponies claimed for their newer PI (Power Improved) cousins. Through extensive dyno and flow-bench testing, Livernois has determined that a lot of the PI's improvement can be attributed primarily to its intake manifold, and secondarily to its revised intake valves, and camshafts, rather than to the heads themselves. Not to put too fine a point on it, the old, non-PI manifold was crap.
http://www.mustang50magazine.com/techarticles/m5lp_0406_mustang_cylinder_heads/index.html
Don't relegate those non-PI heads to bass-boat-anchor duty just yet. The ever-inquisitive minds at Livernois Motorsports have discovered that those much-maligned castings, as fitted to '96-'98 GTs, weren't quite the restrictive corks we all thought them to be. With a little touch-up work-and the proper sup-porting cast-they can support big power. More surprisingly, it turns out that even stock non-PI heads can do a decent job if you feed 'em properly.
You'll no doubt remember that the wheezy first-generation modulars could manage only 215 factory-rated horsepower, compared with the 260 ponies claimed for their newer PI (Power Improved) cousins. Through extensive dyno and flow-bench testing, Livernois has determined that a lot of the PI's improvement can be attributed primarily to its intake manifold, and secondarily to its revised intake valves, and camshafts, rather than to the heads themselves. Not to put too fine a point on it, the old, non-PI manifold was crap.
http://www.mustang50magazine.com/techarticles/m5lp_0406_mustang_cylinder_heads/index.html
