Technical what motor do I have?

1950 GMC C300, it is a dump truck, with duels, I am confused about the motor, some places say that it is a 248 other say 216, I need the intake/exhaust gaskets, how do I determine what I have? Where are the engine numbers, and how to decode? thanks

 

Here are the GMC options engine wise for 1950. I stole them from a website, I am in no way a 1950GMC expert. If nutin else you can rule out 216.

This is no help but some times it takes a nudge on this site.

The 1950 GMC base engine for the half-ton pickup was the 228-cubic-inch in-line six-cylinder. In contrast, the base Chevrolet model featured the smaller 216.5-cubic-inch straight-six. The 93-horsepower 228 had a 3.6-inch cylinder bore and a 3.8-inch stroke. The 228’s compression ratio was 8-to-1. The optional 110-horsepower 248 straight-six had a 3.7-inch bore and 3.8-inch stroke and 7.5-1 compression. The biggest powerplant available on the GMC truck was the 115-horsepower 270 six-cylinder with a 3.7-inch bore and 4-inch stroke. The 270’s compression ratio was 7.5-to-1. Canadian versions of the 1950 GMC truck were equipped with Chevrolet’s 216 straight-six with 228 and 248 available as options. Another significant difference between the GMC and Chevy models was that the GMC used a six-volt positive ground electrical system, while Chevrolet was equipped with a six-volt negative ground system.

 

PnB

Reading the stolen verbage, it said Canadian GMCs could have the Chevy 216. Given that the OP is in Minnesota, there IS the possibility of his truck being Canadian...until he confirms otherwise!

 

This is a 1.5 to 2 ton, and the one archive I Google shows a 248, but where are the block numbers located? I want to be sure before ordering parts

 

I can't imagine that they would put a 216 in a dump truck but stranger things have happened. I pulled a 283 from a '59 small dump truck (2 ton) once.

 

Scrape the pad right behind the distributor. It'll start with 228, 248, or 270 - IF - it's still a GMC. Many, many GMC trucks got blown up, then when the owner found out how much parts cost versus Chevrolet parts, in went a used 216 or 235. One or 2 pictures will tell us in seconds what you have.
There's only 2 types GMC 6 manifold gaskets - small port & big, so unless you have a genuine 1950 270 H head, it'll take the small set.

 

For Chebbies the location is supposedly like this -
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsmA2.htm

 

And the GMC has 5 freeze plugs. Chevy has only two as I remember. Maybe three. But less than 5.

 

The GMC engines are a few inches longer than the Chevrolet. Most GMC,s have the oil filler located on the road draft tube. The Chevy oil fill was in the valve cover.

 

GMC 6cyl valve cover bolts are almost centered in the cover Chevys a more to one side.

 

As suggested, for GMC just check the stamped numbers right on the pad by the distributor. First three numbers are the displacement.

Another way too easy way is look for the embossed "GMC" on the top of the valve cover, seen this on many GMC engines.

 

I believe all the big GMC's also had a tag inside the glove box that states the cubic inches. If it still has the original motor.

 

Ok when I find the numbers, where do I go to get the gasket?(intake /exhaust)