NP 440 swap

[dieseltech619]

I have done a lot of searching on this subject and there doesn't seem to be a ton of info and what i have found all seems to be different in one way or another so i still have a few questions which i think i know the answers to but would rather not have any surprises. I scored a complete gm unit this weekend bell housing trans and shifter. The swap looks pretty straight forward, my truck is 3 on the tree with a bell housing mount not a rear trans mount and the np440 bell doesn't have a provision for a mount.
1st. i need to install an automatic trans style cross member and mount right?
2nd. will the factory clutch linkage work or will i need to modify it in anyway?
3rd. will i need a high hump trans tunnel?
4th. How well does the overdrive perform? How much of an increase in fuel economy did you see? and also what engine and rear gearing are you using?
5th. The trans also came with the flywheel and used clutch, PO converted to automatic so his wife could drive the truck also, Will i be able to use the flywheel my 307 already has and i believe the trans calls for an 11" 10 spline clutch i should just be able to use a factory replacement for a 81-87 c-10 that was originally equipped with the trans right?