I know that this has probably been done to death , but I'm going to ask anyway. I have a set of ECG-D heads and am wondering what mods should be done ??

I'm building a fairly mild street 272 and want to know what can be done porting & valve wise to get the best out of them. Do I need to go bigger valves ?

Block is .040 , cam - intake 0.4201 lift, 282' - exhaust 0.4186 lift ,281' and will probably be running my offy triple carb manifold with 3 "94s"



Also could somebody please tell me what the go is with posted & unposted heads ??



Thanks David

 yblock32

Here are some links to past threads about posted heads.

Advantages of posted heads

Identifying posted heads

 

Performing a search will bring up some more.

Lorena, Texas (South of Waco)

Yblock32,

If the memory is right, the ECG  D heads have the combustion chamber that "wraps around" the valves, something like 220 or so degrees.  Looking down on the head's bottom side the deck portion of each chamber forms something similar to a letter m.  Check and see.  If correct the design looks like it shrouds the valves significantly, possibly offsetting gains of larger valves.  I recall looking at the chambers and thinking that with the wrap around they may have a relatively small volume, so it would be good to cc and find out where you will be on CR, and if you do please let us know the results.

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.

Ted

Have you ever seen any of the non posted heads fail?  I have only seen one head on a small block chevy fail, but it was cut .120 on the deck and the compression ratio was 12 to 1.

Gary Ryan San Antonio.TX.

Gary,

       The faiures first appeared on Blown cars, which is why the posts were added. I doubt if it ever happened on a normally aspirated motor unless somebody milled them a quarter inch or so!

Frank/Rebop

Bristol, In ( by Elkhart) 

The heads technically do not fail by breaking but they will not hold an adequate seal at the head gasket when milled excessively.  At 9½:1 CR, the gasket seal is marginal at best with moderately milled non-posted G heads but at 10½:1 CR, the head gaskets fail consistently on those same cylinders that were later posted in the heads.  Detonation was the root cause in a recent instance that comes to mind but the milled non-posted heads simply forced a much quicker head gasket failure as a result.  Using a pair of posted heads and slightly lowering the compression ratio solved all issues in that particular case.

 

Talking scrub and Yblock regarding head construction is analagous to comparing apples and oranges in this case.  The non-posted G heads have two cylinders in each head that have large areas of unsupported head deck surface that with any significant milling to these heads simply allows too much flex at the gasket seal and results in a head gasket failure.  The posted heads pretty much eliminated this problem while also permitting a much deeper cut or mill to the heads without the aforementioned gasket problems.

 

Here’s a link to previous discussion on how much head milling is generally acceptable.

http://www.y-blocksforever.com/forums/Topic16300-3-1.aspx

Performing a search using head milling will bring up other threads on the subject.

Lorena, Texas (South of Waco)

Thanks to everyone who set me straight on "posted & "unposted" heads. I'm a novice with much to learn - thanks.

I also asked about porting these heads , has anybody got any tips ??

Thanks  david

I wouldnt do anything to the heads, even rebuild them, until the combustion chamber volume is known.  With the cam duration you will need as much CR as the 272 can give.  To throw out a number, say the volume is 78 cc.  Then the CR is going to be way down, and it would be best to look for other heads, C's, G's or 113's.  If the piston to deck clearance is excessive, that compounds CR problems of high volume heads.  A really low CR matched to a 280 duration cam is going to be a dog below 2500 rpm, maybe 3000, and you wont be happy.  What compression does the cam maker specify?

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.

David: According to the Mummert/Reese Head chart, those ECG-D heads were std on 55 Ford cars & were advertised at 7.6 C.R. on a 272, and that was likely optimistic. The footnote says that C.R.s with modern head gaskets are even lower. As previously mentioned, those heads are not likely the answer on a modified engine.

Paul

David: Further, I forgot to mention, that while Offenhauser is a storied name in racing, if really looking for a performance boost, their intake has been analyzed and is likely the poorest internal design of the Tri power setups available. Sorry to rain on your plans, but thought you should know..

Paul