New to the Y-Block, so take it easy on a rookie!

Just purchased a '55 Mercury Montclair with, I assume, a 292.  I've found several resources for factory specs which reference the Champion 870 spark plug.  According to their reference material, the 870 is a 14mm plug, but the car actually has 18mm plugs in it (Autolite AP46).  Could this mean this engine has different heads than '55 factory versions?  Are there others that fit?  I haven't looked for casting numbers yet--I was hoping some of you could solve the mystery for me.  Maybe the mystery is just me!

The car failed emissions, which I half expected.  I'm going to do a basic tune-up ... points, condenser, coil, plugs, timing.  Even though the plugs look OK, the state smog czar says it's rich.  I thought about going to a hotter plug, and try to lean it out a little.  Any advice?

Welcome to the forum SB. Pretty rare anyone gives anyone a hard time in this forum. Lot of good guys willing to share thier experience and knowledge with everyone. First I suggest you ID your block, heads, carberator and intake manifold so you know exactly what you have. Only way you will ever know for sure is to just get this over with. Get yourself some gas, a scraper, brush and get those ID's. Eventually, you will be held hostage to knowing this information, if not now, later. But not much later, lol.

Darrell Howard Whitefish, MT Outlaw 56 Ford F-100's

I'm not sure what resource you're reading, but the 14mm were used in '54 Mercury's only and the plug size was changed to 18mm in 1955 and beyond. Where are you that you need to pass emissions in a '55 Mercury?


Marc

'54 Merc ragtop

Pt Townsend, WA   

                                                                                                                                   

I'm not sure what resource gives you info that 870 plugs are 14 mm, but they are 18 mm plugs.  They were replaced by the F14Y way back when.  Your 46s should be fine for your engine.  Make sure your vacuum advance is working, it's the only advance your engine has.  No advance will play havoc with your emissions reading.  Also, at the top rear of your carburettor fuel bowl is a brass plug, about an inch in diameter, with a screwdriver slot.  Make sure that plug isn't weeping fuel into the secondary throttle bores, that will make it run rich.  I wonder who set the emission standards for your car.  The factory didn't.

John - "The Hoosier Hurricane"

re emisions. in bc canada to get colector plates cars must go threw air cair 1 time only. tho if 1 lives wher air cair is not avilable it is not required. gov run insurance hear i lower mainland is insane. tho it will stop doing air cair next year.

Darrell mentioned ID the various parts of the engine, which is probably a good ides.  A really good resource for ID info is John Mummert's site.  http://www.ford-y-block.com/     It's been extremely helpful to me in figuring out what people have done to my car over the years.