Replacing 4.3 VP engine with Jackshaft and DP-E

[japdip]

So, Im picking up a new 4.3 engine Friday and in prepping for the install, I started tearing the old one out. So of course after looking everywhere for jackshaft information, none look like the setup I have. It appears to have some kind of flange coupling on either end, but they appear to be bolted together steel disks not separated by rubber like I would think. Of course the engine end spline is frozen in and Ive been PB Blasting it every day. I thought I could undo the bolts on the engine end coupling but they are pretty stuck too. Not sure if I should sawsall the nutted end (I think there's 4) or the allen heads on the other side of the flange ( x6). Any ideas on getting this undone to get the engine out? Also, since there doesnt seem to be a u-joint in the jackshaft, wouldnt it be a good idea to put some sort of flex coupler in line?