351w

The 351 Windsors didn't have 2-barrel and 4-barrel heads, but the Clevelands did. Cleveland 4-barrel heads had bigger ports and valves, although the 2-barrel heads still flowed well. I have a set of D0OE 351 Windsor heads on my 289 Mustang. They're OK, nothing special...they have a smaller chamber than later 351W heads. I had the machinist cc one of the chambers, and it came out at 58.5cc after a bit of milling. That equaled about 9:1 with flat top pistons in a 289. I didn't check any closer than that because I'm not dealing with a fast car here, so I don't care THAT much. :)