Ok thanks loving all the info I get here, at the moment it's in the sump keeping everything nice and oily so it doesn't rust up inside. I only bought the GTX because Repco was clearing out the small bottles cheap when I went down to get a new spark plug and it happened to be Castrol 20W-50 as stated on the service sticker so I figured it would be o.k. It was cheap enough to pour back into the bottle and use it for something else, it still may be a long way down the track before I mount the engine back on and start it up so I will look into it when it's ready to go. Should of taken note of those old Castrol GTX2 adds in the 80's "Oils ain't oils"
