From 460 website
The early iron castings, C8VE,C9VE, and DOVE heads are basically all the same. Some castings have thermact-air bosses and drilled passages, and some do not. The size of the thermact-air bosses also varies. With-in the three casting, there is also engineering revisions, i.e. DOVE-A, DOVE-B, DOVE-C. Chamber size is about 77 cc, and can vary +/- from that. The stock size valves in these heads are 2.08 for the intake and 1.65 for the exhaust. These heads can have 2.25 intake and 1.76 exhaust valves installed. The exhaust port shape is restricted quite a bit, and porting helps. After proper porting, all three casting flow the same. It should be noted, not only for these factory cast iron heads, that not only should the exhaust be ported, but the intake as well.
The next batch of casting is; D3VE, E6TE, and F8TE. These heads are basically all the same. The E6s and F8s were cast as replacements for the D3s. Most of these casting have thermact-air bosses and drilled passages, but a few D3 castings do not drilled thermact-air passages. Chamber size varies from 92 cc to 100cc, so it is important to cc the heads. The chamber is .100 deeper than the early heads, and the valves are shorted that much as well. When replacing these heads with the early heads, the valves will be .100 closer to the piston, so take that into consideration. The stock size valves in these heads are 2.08 for the intake and 1.65 for the exhaust. These heads can have 2.25 intake and 1.76 exhaust valves installed. The exhaust port shape is restricted the most out of all the factory cast iron heads. After proper porting, all three casting flow the same. The exhaust cannot be make to flow like the early castings due to the short-turn on the exhaust being .100 shorter.
Maximum Valve Lifts With Stock Heads
Courtesy of Randy Malik
Unmachined D3's with production length valves and stock retainers will allow about .560"valve lift MAXIMUM; maybe some heads might allow very slightly more.
Maximum Power from Ported Heads
Courtesy of Scott Johnson
With well worked max effort dove heads you can expect a maximum of about 700 to 725 HP given the intake port flow capabilities of the dove intake port.
On a 557 cubic inch motor, you can get 700 HP at 6K rpm with a Comp Cams XR292R cam and 10.6 to 1 compression ratio.
A 472 can make 718 hp at 7200 rpm with about 20 degrees more duration, higher valve lift and two points more c/r.
