I have found a 272 that has been machined to 0.060 over. The deck is flat. The ECZ-G heads are flat. No machining required. I know the heads have been machined before. Not sure about the block. Here is the question. Long or short push rods? Does it matter? I was planning to use a short set but after thinking it over and factoring in the fact that the head gaskets are thicker than originals and I'm using the lower ratio rocker arms. I'm leaning towards buying brand new longer ones. Better to adjust out some extra length than try to adjust for shortness. Thoughts? JJ

Link from the opening page to John Mummert's site. He gives general recommendations on pushrod lengths. However, that may be effected by say milled heads & or a decked block. The heads can be roughly checked on the protruding tabs on the corner. Stock should be close on 1" thick. The "G" heads are usually non posted & have somewhat thin decks. Our moderator Ted, does not recommend milling them more than 0.025 thou. If your engine is decked & milled, you may need a recommendation from someone like Ted or Mummert on pushrods..  


Paul

With only moderate milling on iron heads and the decks and assuming the camshaft is no more than 0.450” valve lift (and not a regrind), an effective pushrod length of 7.950-8.000” works for many of the Y engines.  As the camshaft increases in valve lift, the base circle is reduced which in turn requires a longer pushrod in which to compensate.  There is a little leeway in the pushrod length when switching to composition head gaskets.  Because the composition head gaskets are roughly 0.020" thicker than the original steel shim head gaskets, then you can automatically mill up to 0.030" off of the decks and heads before being concerned about intake to head fit and/or pushrod lengths.
 
To accurately measure the effective length, you need a 5/16” or smaller steel ball that will fit inside the cup end of the pushrod and then measure the overall length with that steel ball in place.  Subtract the diameter of the ball from your measurement and you’ll have the effective length.

Lorena, Texas (South of Waco)

Ted's answer to your pushrod length inquiry was informative for me, too, JJ 

Coming at your question a different way, FoMoCo moved from their steel single piece design 'knitting needle' type pushrods to tubular type units in (I think) 1960.  Someone told me that the Ford y-block tubular type O.E.M. pushrods are rated as dependable for a 250# valve spring open pressure rating.

For your and my purposes, the tubular design y-block pushrods are MUCH less prone to bending than the '54-'59 (?) FoMoCo design 'knitting needle' style pushrods.

As Paul suggested, one source for the different length tubular pushrods is John Mummert.  See his listing on the following web page
http://www.ford-y-block.com/valvetrain.htm

Hope this helps. 


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Thanks so much for all the thoughts. My thinking on this is: If the pushrod is the wrong length ( and we are not talking about inches here, 1/16 to 1/8 is the difference) isn't the adjuster on the rocker arm that contacts the push rod just like an adjustable extention to that push rod? Any difference in length at that small amount should be rectified by adjusting ,no? Don't get me wrong, I'm not talking about running the adjuster to the extremes to make up for ridiculous amounts. That would clearly leave no room for future adjustments, but I think it should be ok? The static geometry is from the none adjustable pivot point to the valve tip. This angle won't change when adjusting the push rod adjuster. Thoughts?

The standard pushrod should work fine for you.

The adjuster screw should make up any difference though it is not exactly an extension to the pushrod.  Any time you change the position of the screw, you change the ratio of the rocker and that has an affect on geometry and valve actuation.  Take a look at a rocker arm from the side.  You will see that as you turn the screw in, the ball moves away from the shaft centerline and as you screw it out, it moves towards the shaft centerline - that changes the rocker geometry, which changes everything else.



Lawrenceville, GA

Thanks again. Gonna check that as soon as I get home. I'll post what I find.

Thanks again. Gonna check that as soon as I get home. I'll post what I find.