Hey guys what viscosity oil should i use for my 96 TE running at 314thousand k's?

I used to use some Mitsubishi oil in my Magna (10w-40) should i run this in the Magna or use some other brands ?

if its not using or leaking out, dont change brand or viscosity,
if its starting to use oil, here are 2 very good quality options to suit your cars needs:

penrite everyday driving 20w 50,
http://www.penriteoil.com.au/products/motor-oil/everyday-motor-oil/everyday_driving_20w-50.

or nulon 20w 50
http://www.nulon.com.au/products/20W-50_High_Kilometre_Engine_Oil/

i would go for either penrite or the nulon here.
both are available at super cheap (last time i checked) for probably the best price

if you are looking for cheap, good quality oil go for the nulon though, there will be not much difference except for price..

I just bought the car and dont know what grade is in it, or how often it has been serviced

mmm, if you cant see in the service book, i would use one of the suggestions above, but pay really close attention to it.

i would also check your current oil, if it is very dark & burnt, i would drop the old oil, get some wynns oil flush, and put it through with some cheap gulf western oil. let it idle for 10 - 20 mins, after the engine gets to temp. then drop the oil and filter and replace with one of the above oils and a mitsu or ryco z456 (some will say not ryco, but i havent heard of any trouble, only, "a friend of a friend whose a first year apprentice said.....")
this way you know you are starting fresh.

but should i really be going with 20w-50?, i know it has done alot of K's but i just think an oil that thick on my motor will cause a bit of a lag on the components and i have enough issue with that on other cars (cold, driving is no fun at all with 20w-50).

Also im a big fan of Valvoline's new range of Oils whether it be 20w-50 or not.

it states in the manual to use 15w 40 or 50 on a new motor, and i have been using 15w 50 for about 50,000 now and its by far the best oil i have used. when i started using 15 50 my car had done less than half what yours has done, i would be more inclined to use the 20w 50 because its getting to that age. but like i said, if you can find out what you have in it now, just use that.

also, use whatever brand you like, those were just 2 suggestions of suitable oil

have a read through this (http://www.aussiemagna.com/forums/showthread.php?t=75823&highlight=oil) thread, there are a few oils mentioned in here. 20w 50 is not too thick for your car, i think if you were to use 10 or 15w your car might drink it. lots of people on here use **w 40 or **w 50

i would try a lighter oil say 10/40w then go heavier if it is using it. The manual says to use the lightest grade applicable for conditions as you get better fuel economy, etc. I dont know why many members use such heavy oils, i could understand if there was oil burning issues. I also find the lifters are quieter with lighter oils.