If it does not have the FoMoCo logo, it is probably not a genuine Ford part.

John - "The Hoosier Hurricane"

My question is; Is the Conformatic piston made by Ford Motor Company? Thanks G.S.

56 VIC  Gene Stoehr Sr.

To my knowledge there were aftermarket pistons made up to 100" o/s, i have 312 + .080" in my sunliner and 312 +.060 are common replacement pistons.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

This post made me scratch my head a little bit. So I went to the stock pile of parts and I dug out a conformatic #1031 3.860 piston that came out of a 57 Bird Engine. Isn't this a FMC made part? Thanks G.S.

56 VIC  Gene Stoehr Sr.

Paul; Thanks for the info, didn't know +.040 312 was the biggest they made, maybe I should have kept them. Also guys here is the formula for figuring the c.i. for your mill---3.14 (pi) x the diameter squared (ie: 3x3) x the length (stroke) divided by 4. That is for 1 cylinder.  These old Ys are some of the most fun motors to work with, so many variations. I have a 55 Fairlane that I've have had for 38 years, not show but still plenty of go. Keep 'em alive.

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Old Y Block

Kerrville, Texas 

Just fo info those 312 .040 over pistons were the largest Ford sold. In a 292 block they worked out to about 306 cu. inches.

Paul

Andy; I bought a re-built short block years ago that was re-built by "Mustang Re-builders" and was told it was a 292. The pistons had .040 on top so I thought it was the basic +.040 292. As it turned out it was a .090 over 292 with  .040 312 pistons. I checked the block numbers to be sure. I ran it for a long time and it never got hot real fast as some do that were overbored. Just a little info for thought.

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Old Y Block

Ted, thanks for the info about counterweight interference with 312 cranks and 292 pistons. I never would have guessed there would be a problem.

Best regards,



Paul Menten

Meridian, Idaho

Factory seal diameter for a 272/292 is 2.620”.  Although the 292 neoprene rear main seals give no problems with the seal journal being at ‘spec’, there’s no reason that the journal diameter for the seal cannot be as much as 0.005” over spec.  That only makes the seal 0.0025” higher per side which isn’t much but may give some additional latitude once wear starts setting in.  I always make the seal diameters on the turned down 312 cranks slightly on the large side as it doesn’t hurt anything doing so.  Always better being too large than too small.

 

Here’s a previous thread on the subject.

http://www.y-blocksforever.com/forums/Topic12519-3-1.aspx

Lorena, Texas (South of Waco)

John, Please let me know what the rear main seal seal diameter should be if you use a 312 crank in the 292 block. Thank you.

                                                                 Craig Seyfried