Thanks for the post, unknownroad-- Yea, the front seat room is actually pretty tight. Don't plan on doing anything about that or intruding much into it if I can help it.
I also don't know how structural the firewall is and if I can get away with cutting and boxing it some while the car is fully laden (IE windscreen, dash, and doors are all impacting it some, I'd imagine).
Brakes: Since there was an engine fire, I'm not going to expect to use the existing brake master/booster. If I'm going to replace it, I'll go ahead and look for something that's hydraulic like you suggest-- maybe even the one out of the truck... Thanks for that, btw: I wouldn't have known/thought of that issue with the vacuum.
I'm leery of cutting it, too, but I will at least be nothing it a bit to give clearance for the edge of the oil pan.
After spending time looking at it some more (since I can't work on it for another week) I think what I need to do is raise the body some on the rails-- maybe put an additional 2" or so of spacer material in there where it's already got 2" of rubber in there... I think I can get away with it aesthetically since the frame would look a lot like an extension of the lower side valance-- this will allow me to keep the engine higher in the engine bay and allow the hood to close without mods, allow me to have the tranny up higher with less support intrusion into the footwell (the tranny support that I'll likely take from the truck goes above the tranny and will require me to box the rear part of the footwell 4" or so I'm estimating.
Weight: 721 lbs dry for the engine.
RE: steering linkage-- I just popped the joints so that crosspiece isn't in the way while I'm checking out the other clearance issues.
To recap, it looks like I'm 1) raising the body some on the frame rails 2) opening up the trans tunnel and boxing the rear portion of the passenger's footwell 3) boxing the firewall a couple of inches 4) modifying the oil pan 5) notching, boxing, and triangulating the crossmember, 6) figuring out the brake and steering thing(s)
Folks, please feel very welcome to comment and offer suggestions-- it's not like I've ever done this or anything like this before...