I've been following your thread on Mud and it is interesting. Personally, I like the simplicity of the F engines without the smog equipment but I don't know that I would go through the process of a desmog if my smog equipment was working and serviceable. I'm sure it robs some power, but I don't believe it is enough to notice.
From what I can tell, you are not that far away from being able to get rid of most everything smog related. In very simplistic terms, you will end up with a 2F that looks like an F. The one constraining factor that I see is your carb. That is to say, you don't really know what you have to keep (or can toss) for the carb in your truck - so eliminate the constraint and swap your carb in favor of:
- Trollhole carb - linkage and de-smogged
- 1974 DD38 Aisan - linkage and de-smogged, needs to be drilled for ported vac.
- 1970 to 1973 DD38 Aisan - cable activated and de-smogged,needs to be drilled for ported vac.
As your truck is set up with linkage versus a cable, the Trollhole carb will be easiest (basically plug and play) whereas all the others (except Weber) may need some modification. A two barrel carb with mechanical secondaries and ported vacuum works just as well on a 2F as it does on the F
You can keep your 78 electronic ignition. It is a very good (and serviceable) ignition system. I've run a 78 dizzy (vac retard) with the vacuum ports capped off for a year. There is not anything wrong with running the truck with just mechanical advance; I did notice an improvement once I added ported vacuum (and vacuum advance) - but I got everywhere I was going without it too. That said, it is pretty easy to "upgrade" to the 60 series big cap dizzy and have it recurved or run an HEI dizzy. The HEI is a very straight forward swap.
The 2F that Randy put in the Blue Mule is from an 80 2F. The smog equipment has been removed and it really looks pretty much like an F engine in its simplicity - he just moved over all the F.5 accessories. IIRC, the 2F Kvanoort put into his 1972 is pretty much the same.
On my truck, vacuum connections exist for PCV, brakes, transfer case and dizzy - and it is only recently that I added the ported vacuum for the dizzy.