I bought some used gauges and the oil pressure is a mechanical gauge what is the benifit over an electrical and how is the best way to run a line to my dash, does it need to be a braided line?

i have mechanical oil guages in my cat,more accurate than electric,i used 1/8 plastic line,but i ran the line inside on -3 rubber hose,to protect it from chafing or rubbing against something sharp.

would not suggest the little plastic tube deal regardless of how its protected as the ferrul arrangement where it attaches to the gage and engine fittings are fragile and easily damaged and leak . in long run applications use a dash 3 or 4 push lock rubber or cloth braided hose with the proper fittings and adapters . cheap and bullet proof. don't use stainless braided line as it has a bad habit of chewing its way thru anything it rubs up against and there is no need for it anyway..

As stevesxm said, nylon braid hose or push-lok works good if you want to make your own hoses.

I don't recall seeing these in the past at summit but like the looks of it:
Push-lok:

http://www.summitracing.com/parts/FRA-862004/

http://www.summitracing.com/search/B...?Ns=Rank%7cAsc

AN to NPT fittings for engine end, usually a 1/4 NPT > http://www.summitracing.com/search/P...+to+an+adapter

Adapter to go from gauge to AN fitting > http://www.summitracing.com/parts/AER-FBM2721/

You could also go to your local Parker store and have them make you something in a rubber hose and crimp the fittings on.