Welcome Victor,
I've been lurking around this website and these discussion forums for about 4 years. There is a wealth of knowledge here about old GM trucks. You did not say if you had a 1/2-ton, 3/4-ton or what? Only a 1 1/2 or 2 ton 1950 would have come with a Hi-Torque 235 6. Yours probably started out with a 216. A lot can happen in 50+ years, as others have said, so don't know about yours. Do search this website for specific topics and questions. Under the photo gallery is a great pic of a 47 216 Thriftmaster 6. Find that photo: does yours look like that? Side cover come up around the spark plugs? Valve cover with studs thru the top? Hands down the easiest and simplest swap is a 235 or 261. Be careful of the water pump with a 55-2nd - 62 235. There are a lot of purist here who insist on stock/original only. Don't let them scare you, it's your truck, do it how you want. I would recommend you take your time, though and plan ahead. Good Luck! and have fun....
Frank
