I am looking at buying a cleveland engine. The guy has told me it is a 351. I just want to check if his information is correct. The engine number is JG35SS61934K.
I also have a xb wagon which i bought off ebay. Was told it is a 302. Engine number JG35RD81057K.
Now does the K on the end mean it is a 351 or a 302.
Any info on this subject would be appreciated.

Anything post XA i think (i could be wrong ) K meant factory V8 weather it be an 302 or 351.
Best bet would be to check the stroke lenght or remove the sump & see what is stamped on the crank
302
351
or if your lucky 4MA.

Dont trust the number info because it may have had different crank & rods fitted over time.
Hope this helps

just measure the stroke.
Take out one or more spark plugs. get a stick or wire or watever. Turn the motor over by hand.
Find where the piston is at the bottom of its stroke. Mark it. then wind it up to the top. Mark it.
Then pull your wire or wat you used and measure the leangth between the marks.
If its a 3inch gap its a 302. if its a 3.5 inch gap its a 351.