What is best/easiest way to pull the engine and automatic transmission from a 1955 Mercury Montclair, keep them together or split them?   Also, so there is no way of telling if an engine is a 312 just by looking at the outside? THANKS Larry.

Pull the engine\trans as a unit. IME In the long run its easier.As far as I know the only way to identify a 312 externally is the  little "button" on the crankshaft flange.HTH

Look for ‘ECZ’ on the side of the block.  While there were a few 292’s with this casting identifier, many 312’s did come with it.  What steinauge says about the 5/16" ‘button’ or raised dot on the crank flange holds true for positively identifying a 312 but not all 312 cranks will have that dot.  There were a number of 312’s that did not have that raised dot on the flywheel flange so if the crank flywheel flange is blank, it could potentially still be a 312.

Lorena, Texas (South of Waco)

I have another question, Is there anything I can do to the transmission to help preserve it, while it is in the car and able to run before I take it out? I have plans for the engine right away but the trans. might sit for awhile.

I've used automatic trans that have sat for years, only thing I did when reusing them was to take the pan off and clean it, along with the pickup, and replace the front and rear seals. Of coarse refill with fresh fluid.

Larry:If the engine is the original in your '55 Merc, it is not a 312.  The 312 did not appear in Mercs until '56.

John - "The Hoosier Hurricane"

To make a long story even longer, I meet this gentleman during cruise night, it is his car, got it from his father, it runs good, does'ent smoke, and the trans. was rebuilt first of the year, he has the paperwork to prove that much. But for reasons I will never understand he would rather have a late model big block in it, so I made him an offer for the engine and trans.  I would like to figure out what the engine is, I am sure that all you guys are well aware that people don't always know what they are talking about when it comes to a y-block.

Larry:I see.  Most Y-Blocks for sale are 312s, because they are worth more.  Oddly, most Y-Blocks purchased turn out to be 272 or 292s, not nearly as rare.  The '55 Merc had a 292 when it left the factory, you are wise to verify what it is before you reach for your wallet.

John - "The Hoosier Hurricane"