Originally posted by JFB #05177:
... D2AECA ... corner of the heads is a "4" ... under the valve cover I only found 2J2 ...
All 1972 - 1974 blocks, and all blocks cast in Australia are D2AE-CA blocks. Both 2V and 4V. If it was originally a 4V block it should have 4 bolt main bearing caps. But ... don't ever let the lack of 4 bolt caps disappoint you about the block. The 2 bolt caps, when tightened properly, are stable to 8000 rpm! Don't ever let a mechanic talk you into aftermarket caps (steel, splayed bolts, etc.) they are not needed for the 351C. A set of main cap studs will help insure the caps are torqued correctly, at the very most that's all you need.
All 4V heads have a 4 in the corner, but only the 1970 heads have a "plain" 4, the 1971 - 1974 heads have a 4 and a "dot" in the corner. As Doug mentioned the head's casting number is actually underneath one of the intake runners, making it difficult to determine which head you have ... BUT ... you can check the casting's date code under the valve cover and get a good idea of which head it is. In your case 2J2 decodes as 1972 September 2nd. Because that head was cast so late in the year, its probably a head for a 1973 engine, meaning it has the largest chambers and the smaller 2V valves.
If the heads are original to the engine, and the engine has never been torn apart, then I expect it to be a 1973 Q code engine with dished pistons, 78cc combustion chambers and 8:1 compression. This would make sense since chassis number 5177 is a 1973 Pantera. The camshaft was ground 4° retarded. It was originally equipped with EGR. Installation of a set of Australian 302C heads (small port) will raise the static compression to about 10:1 without doing anything else. Replace the factory induction with an Edelbrock Performer 2V intake manifold and a 650 cfm or 750 cfm Demon carb with annular boosters; also advance the camshaft 4°. Those 3 changes alone shall increase the engine's pep and horsepower a significant amount.