Fuses and fusable links

[Speedster 229]

Hi all. Thanks for your help so far. Maybe after this project I can contribute rather benifit from this collective knowledge. I'm installing a M&H wiring harness in my 70 1/2 ton which has a new 350 in it. I'm following the wiring diagram posted here several times, http://www.geocities.com/chevroletc1...ngincomp.html,
It shows a fusable link between the positive battery post and the small juction block which is mounted on the inside of the passenger fender. My new wiring harness has the fusable link built into the 12ga red wire leading to the junction box and a fuse holder in the 18ga black wire which also goes to the junction block. Two questions here. With the new wiring harness as described above is the fusable link needed in the wire running from the battery? What size fuse should go in the fuse holder in the 18ga black wire??
There is also a fuse holder in the black wire w/ white tracer running out of the generator & fwd lamp harness firewall connector. M&H says it is to protect the amp meter. My old harness didn't have this or it was cut out . What size fuse should go in this holder?
Last question. Where does the oil pressure sending unit go in the block? I'm using the port behind the distributor for my stock mechanical pressure guage. The pressure sending unit had been removed from the old engine so I'm in the dark on location. Would someone have a part number for a 1970 1/2 sending unit??

Thanks for all the help.

[john]

Your 18ga. black and black/white tracer use 4 amp fuses,and they are for the ammeter.