L96 6.0 swap into 72 longhorn. some questions

[mtdave2]

So after years of debating, I'm finally putting an LS in my ole 72 c20 longhorn. Probably putting the cart before the horse, but, now that I have the motor, I’m starting to work out what I will need to do. So I have a few questions.
Here is what I have
• L96 6.0 out of a 2018 express van 2500 with a 6l90 trans. 9k miles supper nice!
• It does have the e78 ECU (12687342)
• Has the full harness and the gas pedal.

Not as info on this motor swap, so I’m asking here to help me find the info.
1. Clearances.
a. A/C fit in the stock location? Looks like it could be tight.
b. Will the stock exhaust manifolds fit? Or must I use headers?
c. Stock oil pan work?

2. I need to have the ac work. The truck is an A/C and has currently working A/C. can the stock stuff be used and just have hoses made? Or is there a better way

3. The e78 cu, I have read there are issues getting someone who can flash the ecu. What are the options here?

4. Fuel tanks. I rebuilt and coated my stock tank behind the seat and my one saddle tank. Can I use these tanks, leave the lines to my selector valve, then put an in-line pump and filter?

5. Suggestions for motor mounts?

6. Where can I find the pinouts for this particular motor/van?

7. pedal. Anyone ever rig up something to preserve the original pedal. that is mount the pedal to the new pedal assembly.

8. where are most people mounting the ecu? in the cab under the dash? id like to see options

9. need to convert the oil and trans dipsticks from the van to the truck..what motors would use the dipsticks that would work?

There will be more, and I will make a project post of progress.
What say you? love to hear input, not so much on judgment and unhelpful comments.