**GB & a10gf posted while i was typing so they've probably covered it but you get it anyway
Hiya BLL...fairly much need to bolt the G-Box on and do it all in one lump. I did wonder the other week to myself if it could be possible to 'split' the frame and install it to the bottom and then add the top bit of frame (that's how Tonti frame Gutzzlies are done), but I think I've discounted that idea...
The mangled pipe is the breather with maybe a bit of rag in it to keeps crawlies out, probably serviceable but ugly, I'd swap it with something better and connect a hose to it to run to a 'catch' bottle (personal choice) this would need to be addressed before installation, or at latest before adding the Magneto. (it has answered for me what the hole is above that viewed from above- holds the 'P' clip
).
The mounting hole in the case looks deformed from previously being loose, probably ok, but not ideal....Looks like the correct through bolt/mounting bar, but asI have larger holes like that in the frame lugs also, have used a bit of hollow bar/tube through both lugs each side as a spigot, these are not shown in the parts diagram I have, so not sure if they're a 'part#' but'm sure that's how it was when I bought the frame (I think circa '56 year), so reckon they belong....
To install it you'll need to remove the rear rocker inspection cover, and the top (middle) stud of same, otherwise it jams on the frame. I think you need to have the right-front engine plate on, but loosely attached and needs jiggling, but *NOT* the left front, that goes on quit easily after, but no way in hell of glory with it on.
For some reason, I'm thinking it was also easier with the timing cover(s) of, but not sure- you'll need to obviously remove the outer to put the genny in but no point if no need....
Can't be certain, but I think the lump goes in best from the right..(because of the right plate being loosely 'on').or maybe the other right..
...I've heard of some guys laying the whole show over, and lump on it's side so it can be lifted in, but that sounds harder to me....when i did mine, I sat it on blocks of wood at about the same height as the frame rails, and did my best to cover the frame to not scratch it....
Just had a call for work in the morning so'll sleep on it....I'm sure you'll hav eothe input in the meantime..