I always used dot 3  back in those days and never had any problem with it but since evtg is new and i 'm on a fresh start i might as well inquire.

The dot 5 is three times as expensive and as i don't intend to race the  car in any ways I don'think i'll abuse the braking system as it will over heat.

I jus heard though that it's more stable for long time use so... all opinions welcome

I tried to clean with dot 3 brake fluid but they don't inspire me to much confidence anymore so probably better with the cheap hoses Rock Auto sells at least they're new. I can play with engine transmismission and many other parts but not with  the brakes thanks for all those infos 

You hit one of the best reasons - cars that sit. To this day the brake makers still recommend every-other-year brake system flush. Water helps create acids and sludge - and those form solids and eat at the cylinders. 
No system can be sealed perfectly and never need a cleaning, but the lack of affinity for water, etc. is likely the best reason to use the 5. Cars that sit require different treatment vs. those driven daily and serviced on a regular basis.

Yup - you can use any of the inexpensive modern tools, some costing less than 20 bucks, or do as I've done on many of my cars - gravity bleed. Open a bleeder, put a hose on it and the other end in a container and let it run until it runs clear. Do that all the way around. You can be off doing other things while it bleeds. 
It's harder on some cars with all the valving, but I was still able to do my 73 for the most part via gravity bleeding. 

The reason? It takes, as I recall, about 80 psi DIFFERENCE between the two sides to trip that switch.
With a combo valve like I have, it's SIMPLE to reset it. When you buy them they try to sell you their special tool to hold the shuttle from moving - the catch is that the shuttle can be reset, thus the switch turned off, by opening the other side and applying pedal pressure JUST until the light goes out.
Been there, done that - bled hundreds of systems (including all of my own in the last couple of years) and nary a problem.

I have the tool that you had to use on Ford systems - it's a metal piece you screw in in place of the switch core but haven't used it much. 
Pressure bleeding with a pressure tank, etc. doesn't use enough pressure to trip the switch, and gravity bleeding uses no pressure, and the vacuum pump tools also don't create enough pressure differential to trip the light.

On my 73, I tripped the light but it went out as soon as I opened the front bleeders and applied some pressure. As quick as the light went out again, I let up and closed the system.

I recommend against the pump it up and have a friend open the bleeder method on cars with older cylinders as that forces the cups of the master into territory that's not been used in how long - that's where sludge, dirt, whatever, forms and you can make a working master worthless.
If your master cylinder is old, don't allow the pedal to go down below normal position as it may just end up cutting the cups on dirt and sludge.
Those master cylinders can be nasty if they've been forced into areas they've not been into in a while.

 i'll throw in an all new mc, all new rear cyls, new power booster, rebuilted ss sleeved callipers, and new  lines. I'll check the switch and see if it can be cleaned and reused, or call new one. I'm an old timer and will use a friend to push and hold the pedal but first got to get the engine back to life hope next week. 

the contamination was worst then i tought so might be using dot 5 for that summer driven car