Reply to "Head info"

If the engine is 100% stock there's plenty of "other" ways to determine what you got. The cast iron intake manifold makes it a slam dunk because D1ZE heads were used in conjunction with D1ZE intake manifolds, D2ZE heads with D2ZE intake manifolds, D3ZE heads with D3ZE intake manifolds.

D0AE intake manifold used in conjunction with a head that has a 4 in the corner means you have D0AE heads. D0AE intake and heads that have a 4 'dot" in the corner makes them D1AE heads.

Only cobra jets had dual point distributors, single point distributor means you have an M code motor, M code motors had heads with closed combustion chambers.

D0AE heads have the smallest closed chamber style combustion chambers, nominally 62.8cc, and of course the big valves.

D1AE heads have nominally 66.1cc closed chamber style combustion chambers & big valves.

D1ZE & D2ZE heads have nominal 75.4cc open chamber style combustion chambers and big valves.

D3ZE heads have nominal 78.4cc open chamber style combustion chambers and the smaller 2V valves.

Reworking D3ZE heads seems a complete waste of time to me because D1ZE & D2ZE heads are cheap enough to obtain on eBay. The best heads are the D0AE heads & the D1AE heads aren't too far behind. These are the closed chamber heads, they sell for more money.

Ford's 1970 & 1971 351C compression ratio figures are in error. Either the sales department miscalculated the compression ratio, or they were intentionally misleading people. The actual compression ratios are:

1970 4V = 10.0:1
1971 4V = 9.7:1
1971 cobra jet = 8.8:1
1972 cobra jet = 8.8:1
1973 cobra jet = 8.0:1