Installing tach and oil press guage

[74 challenge]

I'm not an expert at witing and I know that under my dash is a spaghetti factory and could use all the guidance I can find to locate the following wires so I can tap into them.

Ignition/ switch power- for both gauges
Dash lights - for both gauges
Engine ground for both gauges and lights - good communal ground?
Coil wire I will have to run to negative side of coil.
Oil pressure wire I will have to run to sender

They recomend a fuse, I'm assuming to do this right I should put one in.

Any input appreciated.

[FY1Cuda]

The bottom of the fuse block has two spade connectors--one is always hot and the other (ACC) is hot when the ignition is on.  You can get power from those or tap into the fat red or black wire coming to (or going from) the ammeter on the dash.  On a '70 the dash lights are fed by orange wires.  I'll presume the '74 is the same.  The body is grounded by a wire from the negative terminal of the battery to the radiator support right by it.  The engine is grounded similarly.  Attaching a wire to the dash frame will ground any gauges you're adding. The factory used the #20 spot on the bulkhead connector to run a wire from the tach to the negative side of the coil. The oil sender wire also goes through the bulkhead connector.  You can buy the male and female wire ends for the bulkhead connector and run the new leads through there.
http://www.cuda-challenger.com/cc/index.php?topic=98097.0

Not the best wiring diagram but will help you trace things:
http://www.mymopar.com/72to76_wiring.htm

[74 challenge]

sweet thanks!

I hate almost everything electrical.