Are these heads better flowing than the 1972-74 heads found on a 1974 302?
I have been thinking about replacing them with the E7s to upgrade from the press in rocker studs and rail rockers.
Thought about the GT40Ps but they are weird with how exhaust manifolds fit compared to the plugs, and I was reading rockers are strange too. I don't know in what way though.
I was thinking the E7s could be cleaned up a bit, but how do they flow in stock form?
Thanks.

 

Those heads flow about the same, the early heads have smaller chambers but the later heads have hardened valve seats and pedestal mount rockers, valves are the same size. If you want an upgrade get a set of GT40s(not the P version), these were found on '96-97.5 Explorer/Mountaineers, Gen1 Lightnings, and '93-95 Mustang Cobras, those things use the same pedestal rockers, have larger valves and ports, flow 25% better as cast and were available with 60-64cc chambers depending upon application.