I have a set of 1.54 rockers that would be good to install.  What is the minimum?  Dont recall exactly the clearance figure with the 1.43s before assembly.  The high ratios could be put in place with zero lash for a rollover check.  If no interference occured at least there would be the .017 margin.  Heads milled .035, decked .028, 1.93 intakes, Isky E-4 with .017 lash setting, flattops.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

I don't know what minimum is. If the deck is at 0, then you should have nothing to worry about. The E4 and 1.54 rockers will provide about.436" lift. On Mummert's site, he says over .500" lift, clearance must be checked.


Lawrenceville, GA

Rule of thumb for minimum piston to valve clearance is 0.075” for the intakes and 0.090” for the exhaust.  But you’ll find 0.090” (intake) and 0.110” (exhaust) numbers being recommended in other circles so take your pick.  With the larger intake valves, clearance issues at the edge of the cylinder wall come to the forefront before actual piston clearance does and this is addressed by notching the cylinder walls at the offending locations.  Any head milling that’s performed also brings the valves closer to the pistons or the edge of the block.  Like Charlie mentions, as long as the camshaft is less than 0.500” lift, then there isn’t expected to be much issue in regards to valve to piston or cylinder wall clearance.

Lorena, Texas (South of Waco)