283 for 1956?

[youngerestorer]

Just took my engine to the machine shop, thinking it was a 265. But after they checked the block for cracks, etc. They told it was a 283, so I did some research and I found that the 283 came with a 3 speed manual in '55 and as an automatic in '57. (Hope that is right?!) My truck when I bought it had a 3 speed also. Did some of the 283 engines from '55 carry over into '56 and whether this could be the original engine??? Thanks for any input/knowledge.