Someone over at stangnet posted a pic of some aluminum cleaveland heads that were true 4V - heads (4 Valves per cyln). If I remember correctly, they were also extreemly expensive!
Could you even get a 351W-4V engine in a classic stang? Another thing I've never seen. And how come they have the same engine code if they're different engines? Are you sure you're not just compareing the different M code 351C-4V engines?
And only 15Lbs lighter? I though for sure there'd be more of a difference than that! I figured the Cleveland heads themselves outweighed the Windsor heads by about 15Lbs.
True about the heads.. there is alot of potential still left in the windsor heads. But you can't fit nearly as large of valves in the windsor head. I had my heads machined for oversized chebby valves and (1.94 / 1.60) was the biggest they could fit. I wanted 2.02 intake. While I was at it, I also did a port and polish job (damn thermactor bumps took a long time to grind out!) as well as a gasket match. I was really impressed to read over at fordmuscle.com that when they tested a 351W head prepped almost exactly the same as mine, it outflowed the Edelbrock Performer Aluminum heads! Here's a link to their article:
http://www.fordmuscle.com/archives/2...ds/index.shtml