mick35 - Thanks for posting all the info on your build. I've looked at the Falcon engine over the years and understood that the V-12 was based on two Chevy inline 6's, and that the Falcon heads would fit a 250-292 Chevy 6. Now, with you taking the initiative to actually step up and purchase one, we all get to see what it would take to get one working on a real running engine.
With what you've shown so far, the only similarity between the Falcon head and the Chevy 6 seems to be the bore spacing and maybe the bolt pattern(?). Otherwise with the pushrods outside the block, using the Falcon head looks more like using two (or more) V-8 heads welded together. A lot more work than I originally thought it would take.
I've never been a big fan of using welded V-8 heads on a Chevy 6 mainly because of the awkward way the side cover has to be made. I've got a Ford 6 engine with a head made from three welded 351 Cleveland heads that has the same issues with pushrods. I didn't originally build the engine, but have pretty much set it aside after spending a considerable time trying to get it useable again. One issue was trying to seal all of the oil leaks around the pushrod cover. Invested more than one tube of RTV.
So, when I've thought about doing one of these head swaps (and maybe you've already considered it) is to also convert it to an overhead camshaft. Lots of advantages and probably more or less the same amount of work. The Falcon head is a good candidate because the valves all appear to be inline and you'd only need to use one camshaft. And you already need to build a custom camshaft anyway.
Pete Aardema used to do a lot of overhead conversions, but I don't think he is still around.
https://www.hotrod.com/articles/hot-rodd...inder-behemoth/And I've also heard of circle track racers in the 50's converting stock GMC heads to overhead cams, so it not something new.
Just a thought.
