SOHC heads

[67gt350]

I for one am very glad Jay is doing a FE Power SOHC head, especially with increased performance. Is it wrong to buy the heads before the block??

[fekbmax]

jay has came out with so many quality parts for the fe and more in the works. makes me reluctant to buy any new fe stuff and wait till all these new parts become available.

[67gt350]

I agree ! I don't know how he finds the time! I have been waiting to see if his source for blocks comes through that would be nice. He will have SOHC heads plus his revised rocker arms plus new wedge heads and intakes... looks like we all better start saving to place an order!!

[scott foxwell]

I have a pair of Coon SOHC heads that I bought from Jay, one of the sets that he got in his second batch. I brought them to Brian at R&R Performance in Spring Lake Park Minnesota, the same person Jay uses, since I knew by that time he had some experience working on Jay's heads. At that time Jay had found the Ferrera light weight valves were considerably lighter than what he had been using, so I bought a set of those. Further testing by Jay and Brian found the light weight Ferrera valves are not the best choice for max flow though, but I decided to stick with them anyway. Brian at R&R did the valve job and just a minor cleanup of the port under the valve seat, he did not do any other porting on my set. They are not "as cast", but not too far off. Brian flowed my heads, he also provided the flow figures for my heads but with the Manley valves he and Jay had found flowed much better. One thing this shows is head flow, like everything on a race car, is all about the complete "package" and not just the head casting itself. Jay has covered this topic in the past in one of his SOHC builds, he probably remembers more of the results they found. Here are my flow figures:


Intake

Lift          .100   .200   .300   .400   .500   .600   .700   .800

Ferrera      77    158    225    280    324    345    354    357   

Manley       80    163    239    312    361    381    385    386

Exhaust

Ferrera       53    112    175    208    235    260    280    293

Manley        56    111    174    219    260    285    296    303

Big obvious question...did both intake valves have a back cut? The flow numbers represent something that looks very much like the Ferrea valves didn't, and the Manley valves did.
What happens after .800? (I know nothing about the SOHC head) What size valve and what's the valve job? FWIW I've gotten the best intake flow numbers across the board with Rev valves. I won't use a Manley valve.  The Ferrea Competition valves are very good valves, they just don't flow well for some reason, even with a back cut. Those Manley intake numbers are good numbers.

[thatdarncat]

The head design of the valves is very different between the lightweight Ferrera and the specific Manley, especially the intake valves if I remember. Valve sizes are 2.300 & 1.900. Flow over .800 lift wasn't tested, hard to get a Cammer with much lift at the valve over that due to the rocker ratio, something Jay is trying to solve. Jay did a whole write up on the valve testing back when he was building that particular engine, maybe he remembers where the post is and some more of the details.

[preaction]

361 cfm at .500 lift, clearly quality needs to go hand and hand with quantity I'm not an engine professional but this is a lot going on for 1/2" lift. Would anyone care to comment on how this  could    play out with a 520 CI street build.

[scott foxwell]

361 cfm at .500 lift, clearly quality needs to go hand and hand with quantity I'm not an engine professional but this is a lot going on for 1/2" lift. Would anyone care to comment on how this  could    play out with a 520 CI street build.

My 532ci BB Chev pump gas engines with a 2.3 valve flowing very very similar numbers (within a cfm or two) make over 800hp @ ~6500 and 700 tq @ ~5000 with >.700" lift in the 260 @ .05 range, single 1050 carb. I'd be interested in any cross section information on the cammer heads. The minimum in the BB Chev heads is right at 3.0" sq in. The one big advantage this particular BB Chev combination has is a 4.60 bore x 4" stroke.

[cdmbill2]

I think the bigger question is why the stall on the intake port on the chart shown after .500 lift?

[jayb]

The stock SOHC ports all seem to have that stall, and I think it is just the basic port design.  Factory SOHC cams had lift just shy of 0.600", and of course the intake had to fit under the hood of a Galaxie for NASCAR purposes, so the ports have more of a curve in them than would be ideal.  The port designs I've worked with raise that intake port significantly, and that helps a lot with flow at the higher lift. 

The Ferrea intake valves are a completely flat valve on the back side, with no taper or tulip shape at all, whereas the Manley valves that I've used have either a 7 degree or 10 degree taper or tulip on the back side.  I think this is the primary difference between the valves, and the reason for the marginal flow of the Ferreas.

Back at the end of 2008 when I was getting serious about the port work on the SOHC I got the following intake flow numbers from a raised port head with the 2.300" Manley valve:

0.100" - 83
0.200" - 176
0.300" - 280
0.400" - 361
0.500" - 412
0.600" - 434
0.700" - 443
0.800" - 453

This was on a SuperFlow SF-600 bench and using a 4.500" bore size, which happened to be the bore size I was using on my 585" SOHC engine.  The engine ended up making 960 HP at 6700 RPM, using a Hilborn mechanical fuel injection intake that had been converted to EFI, and raised on the heads with 3/8" port plates so that the ports would line up.  The engine was handicapped somewhat with the 2-7/16" throttle plates in the intake.  Port cross section was about 3.5 square inches (round 2-1/8" diameter port, which is just a hair over the stock size of 2.060").  This engine ran 9.50s and a best of 9.48@143 in my 64 Galaxie, which weighed 3935 with me in it, during Drag Week 2009. 

Since that time of course I've made other improvements to the heads, and they flow a little more now than they did before.  I'm hoping to incorporate those changes into the Australian heads that I'm working on, to make a really high performance SOHC head available.

[Autoholic]

Jay, how much can you change the rocker ratio on the SOHC? What would you do to change it? I don't think you can really move the location of the rocker shaft. Would the solution be a thinner rocker shaft? That could allow you some relocation. I'd imagine you'd figure out what the inner diameter needed to be for oil flow, and then figure out what the outer diameter needed to be for the desired ratio. Then make it out of a strong alloy.

[preaction]

Jay I started this thread because I knew of your working with Bills heads and this web site is the only place these parts have had any conversation on them. Thanks for posting your findings clearly it makes for healthy debate. As a side note I don't think a vendor like Bill deserves support from this community, I do believe the parts will make it into builds just for the fact of supply and demand and the niche market these parts supply.

[machoneman]

Jay, how much can you change the rocker ratio on the SOHC? What would you do to change it? I don't think you can really move the location of the rocker shaft. Would the solution be a thinner rocker shaft? That could allow you some relocation. I'd imagine you'd figure out what the inner diameter needed to be for oil flow, and then figure out what the outer diameter needed to be for the desired ratio. Then make it out of a strong alloy.

See Pages 4-5 for a SOHC rocker ratio back-and-forth.

http://fepower.net/simplemachinesforum/index.php?topic=3515.60

[Falcon67]

I think the bigger question is why the stall on the intake port on the chart shown after .500 lift?

Some ported 351C 2V heads do that at around .450.  I have a set - makes a loud POP on the flow bench when the air fails to make the short turn.  Dramatic.  Low port with flat floor and fairly sharp turn can do it I think.  The 4V heads I flowed with port stuffers that effectively raise the port floor about 3/8" or so did not exhibit any sudden flow changes, they just ran out of increase around .550.  In an ode to "bigger ain't always better", the exhaust on my 2V set flow 220 CFM @ .500, not bad for a bitty port.  The big cleaned up exhaust on the 4V units gave out at 199 CFM @ .500

[Autoholic]

See Pages 4-5 for a SOHC rocker ratio back-and-forth.

Thanks for the link. Looks like Jay already had the same thoughts as I did a long time ago. Sometimes while reading what Jay is thinking about doing to increase performance, I'm reminded of Mickey Thompson and Sneaky Pete Robinson. Those guys explored the SOHC and how to improve it back when it was still supported by Ford.

[preaction]

Jay do you see your new heads doing better than the results of your current heads ?