Here are specifications for the new head

SPECIFICATIONS

VALVE SIZES: 1.94" intake     1.54" exhaust   11/32" stem

VALVE MATERIAL: Stainless steel, hard chrome stems, hardened tip.

VALVE LENGTHS:  5.110"

VALVE SPRINGS: Single spring with damper, 1.250" diameter, intalled height 1.750". 110# Seat @ 1.750"    280# @ .500"   Seat pressure 85# with +.050" keepers.

STEEL SPRING CUPS

Hardened keepers with 1 piece steel retainers.

COMBUSTION CHAMBER:  60cc +-

BARE MACHINED CASTING WEIGHT:   24.5#

DECK THICKNESS:  .625"

VALVE GUIDES: Manganese Bronze alloy

STEM SEALS: Positive type

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

John.  What kind of lift at the valve can be accommodated without major work or changing out the valves to longer ones?  I'm thinking along the lines of 0.580"-0.595" net valve lifts.

Lorena, Texas (South of Waco)

Ted, .600" lift should not be a problem. You would need to upgrade valve springs of course. The heads are cut for 1.460" diameter spring cups and the Comp Beehives are 1.440" so that will be a simple installation. It will require using a spring disc instead of cup. Guide register is .560".

The valves do not contact the deck surface as is a problem with the stock heads. They do eventually hit the cylinder wall at around .800" lift.

Retainer to stem seal clearance will not be a problem.

The rocker bolt pattern will be spread away from the shaft. The shaft can be moved closer to the pushrod side and the length of arm increased from the shaft to the valve stem. This will allow new rocker arms to be built with higher ratios approaching 1.8:1 if desired.

Our major quandry today is a desire to increase the rocker stand bolts from 5/16" to 3/8". This sounds simple but the valve  cover studs become a problem.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

John:

Are the 5/16 rocker stand bolts getting close to failure with the spring pressures and inertia loads, prompting the possible need for 3/8 bolts?  The rocker  cover attachments should be no problem, just run a 3/8 drill through the grommet and use 3/8 nuts.

John - "The Hoosier Hurricane"

John, since we need to make new rocker stands and we're drilling/tapping the holes in the head we can make this change easily, more or less. I don't think that the 5/16" bolts are stressed at current levels but with higher lifts, more RPM ect it could become an issue.

I found that some rocker grommets have a 3/8" hole already, some don't. Either way it is the simplest fix for the problem.

The bolt change is not written in stone at this point.

Part of the reason for considering the change is that our machine only holds 16 tools. Now that sounds like enough until you actually start machining a head. Since the rocker bolts are the only 5/16" tapped hole it would save a tool position and increase the strength. The drill also makes the oil passage to the rockers so it has to be there.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

John, that seems simple remedy to proposed problem, i think we are all trying to help as heads get closer to completion, i was thinking of stepped 3/8 down to 5/16 rod but its more machining etc, i like your idea.  I,ll bet johns thinking its close but yet so far! regards bill.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Ooops!  John just mentioned relocating the rocker shafts.  That causes a problem with the mounting studs, may require slotted holes in the rocker covers, OR special cast aluminum, pretty finned covers to fit the new heads.  John????

John - "The Hoosier Hurricane"

John, I believe the outside studs will stay in the same position as the originals but the inside ones may have to be repositioned a small amount, hopefully not enough that only slight modifications to our original rockers can be worked out and still be used.

-Gary Burnette-

The way John explained it to me was the stock rocker shafts and rocker arms would still work with the aluminum heads but must be used with the rocker arm pedestal supports that are furnished with the heads.  The valve cover studs themselves would still be in the original locations.

Lorena, Texas (South of Waco)

wow, I remember when the discussion used to be someone should make aluminum heads for the y…yea right, like THAT was ever gonna happen.



NOW listen to you guys!

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK