Sorry for derailing your thread with my gripe. I was actually cheering you on - really nice job. I think this (LS9 Pantera) is an awesome project. I think the choice makes a lot of sense over a modern Ford engine.
Referring to the picture. The one on the right has more displacement.
I know which one I would rather work on and try to fit in an engine compartment. The photo is a 4.6L DOHC and a 302, but a new Coyote is not much narrower than the 4.6 and a 351 is not much wider that a 302 (relatively in the context of this physical comparison).
This certainly is not a huge market that makes or breaks a giant corporation. But... if the decision is made objectively (without loyalty to a certain brand or considering past partnerships) modern (note "modern") engines transplanted into older cars, kit cars, race cars, etc., going forward will mostly be GM products due to packaging except for the most die hard Ford guys that go to the extra trouble and frustration. Most (like me) will probably stick with running the 60's era push rods instead.
Ford transitioned to the OHC engines around 1996. These are almost certainly more expensive to produce - not to mention the R&D invested. What did it get them? Refinement? For pickup trucks, vans, and Mustangs? Ability to meet emissions and efficiency regulations? GM seems to have that covered.
Ok - sorry again. I am done. Awesome car.