312 Y block for 223 I6 swap on my Fairlane?

I found a 312 Y for sale in my town for cheap (less than $200) and I figured I would pick it up, rebuild it and swap my old I6 out once it's done. Has anyone done that on a 55-56 Ford and could maybe offer some pointers?
I have the original 2spd auto in my 55, and the motor is at least a 56 since they didn't make a 312 in 55. Should it bolt right up or will an adaptor be needed?
Sorry if these are newbie questions, but I've never swapped a motor myself and there are an awful lot of folks here who could probably do it with their eyes closed so show me what you know!
Thanks in advance -

 

Are you sure it's a 312? Check the block numbers. Is it complete? If it's a 312 for that price, I'd grab it! Can't help you on the swap or ****** questions though.

 

yea... the y-block and the 223 sicks bolt paterns should be the same in those years... i think they were same untill 57?

 

I haven't seen it in person yet, so it might be something else but a local shop is selling it so I hope they know how to tell what it is. It was in another 55 fairlane but they yanked it to put the original motor back in.
Even if its a smaller one, I'm thinking a complete Y any size is worth $200.
My six runs fine (its my daily driver) so I can take my time and build the Y right and then worry about the swap.
I'm gonna grab it and if it doesn't fit, then I guess I'll just have to get a new ****** too - oh well!
Thanks

 

200 for a complete 312 y -block is a good price and if its a 292 its good too.