As fr as your wiring goes, you will need to do all the basic stuff like battery (-) to the engine block; frame to engine block ground strap, also hook a ground strap from one of the intake manafold bolt in the rear to a stud thru the fire wall, (your 302 should have had one on the driver side to the manafold, so rehook it up); start relay to starter cable; the old harness should have a connection for the termperature sender; then there is the oil pressure sender hookup.
I doubt that your 75 460 had many vacuum lines hooked up to it. Most likely it had a connection ftom the main vacuum tree to the brake vacuum booster, there should be one from the vacuum tree to the transmission modulator, if you have cruise control then a connection from the vacuum tree to the servo, and one from the carb to the distrubutor.
Then ofcourse there is the ignition and those connections depend on what ignition system you are going to use.
You won't find a book for this because it is a non-standartd arrangement. You are marrying two systems from different years. You might want to try getting an engine shop manual for the 460 and at least an EVTM for the 86.
Hope that helps, if you have any speciffic questions as you go we will be glad to attempt to answer them. Some pictures along with the question would help also. Like they say a picture is worth a 1000 words so take a picture of the item in question and post it in this thread.
Good luck,
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