I have built FE engines with "0" deck and shim gaskets with no problems. These were with old style combustion chambers. I would not anticipate problems with the new chambers. Ted has undoubtedly built engines with new combustion chambers and can answer the question.

I ahve not yet recieved my "Y" block mag any one else recieved theirs?? I only live about 50 miles from Bruce, maybe I'll have to drive down.

Ted (Quote)On an unmachined and stock Y block and using the stock cylinder heads and composition gaskets, the heads will sit ~0.020” higher than stock if no milling of the heads or decks takes place.



Thanks Ted for that info, that what I was looking for as an engine I am working on has had the deck shaved to get a .020" clearance above the replacement pistons while using steel shim gaskets (.021") to get ~.040" head to deck clearance.



Can you run less a piston to deck clearance with aluminum and still not have detonation issues.



Just looking what changes needed if I put on a set.

marv

This was a core engine that was already 0.060" overbored and simply rebuilt to use as a dyno mule.  The block decks were straight so they were not cut upon on this latest rebuild which kept the pistons at 0.025” in the hole.  The deck side of the heads were cut 0.025” though to give a surface that was smooth enough to seal with.  The iron 'G' heads used for testing had considerable rust on the sealing surface before preparing them for use.  This particular short block was originally put together in the Seventies with the current pistons and it would appear that only a cleanup mill was performed on the block decks at that time.

 

The intake manifold fit was fine on the aluminum heads and no additional work was required as such.  The iron ECZ-G heads had been milled ~0.025” and the same intake manifold fit fine on those also but I typically don’t start to see a problem with manifold fit until at least 0.045”-0.050” is milled from the heads and/or decks.  I didn’t ask John if the aluminum heads were machined with composition gaskets in mind or if machined to the original ‘steel shim’ head gasket specs.  Regardless of how they are machined, everything fits up just fine.  On an unmachined and stock Y block and using the stock cylinder heads and composition gaskets, the heads will sit ~0.020” higher than stock if no milling of the heads or decks takes place.

Lorena, Texas (South of Waco)

Thanks for the detailed graph Ted. You guys have done some great work. 

I don't get Y block magazine (yes I should) I was also interested in purchase details. Also how long before they're ready for release. 

Grizzly (Aussie Mainline)

Great test Ted. Very nice torque and HP curve John. Top quality there fellows and congratulations.

Ted I was reading on you first post about the mule engine and (quote) The engine used for the test is a +060 over 312 with the cast flattop pistons 0.025” in the hole and stock G heads that had only a good valve job with hardened seats installed and a 0.025” mill to clean up the deck side of the heads.

Being the pistons were .025" in the hole did you have to mill the block to get the .025" clearance. If the block was milled did you have to remove material from the new heads intake surface to mate the intake manifold properly or is there enough freedom to install the intake without milling that surface.
marv

Here are a pair of graphs.  The difference in the two carburetor spacer designs is why you test.  A street driver would like the four hole spacer while a racing or ‘spirited driving’ application will prefer the tapered design spacer.

 

 

Lorena, Texas (South of Waco)

Thanks for the clarification Ted, It was the net expansion I was thinking about.

Ted/John,

What are the flow numbers for the intake/exhaust for these heads out of the box versus the g's and where did the biggest improvements in flow come from? Opening exhaust port? changing angle of lower intake port to valve opening? combustion chamber shape and size ect. ect . ect. ?

I will then be curious as to the flow numbers that can be acheived once you guy's start porting them.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

I believe the mag said $2049 if you ordered by the middle of May. I just got my mag two days ago, so I think JM was believing that the magazines would all be in the hands of prospective buyers well before the middle of the month. Unfortunately the USPS got them out a little slowly...

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

I am impressed. Getting ready to pull the 312 from my 57 Bird in a few weeks or so. I will be using a 573 and 94's with Sanderson headers, MSD, etc. Unfortunately, I didn't get the Yblock Magazine this month. I thought my subscription was paid up but I have been living away from the house as it is being remodeled and the mail is a bit chaotic right now. So please, someone post what the expected cost of these new jewels will be.



Thanks,



Mark

57 Black Tbird 312/auto

Impressive!! A 20% increase from the new heads. I, like most, would like to see a comparison chart for the testing done.

It's interesting that there is an improvement, even at lower RPM, with a spacer. I would have thought that the standard heads would be giving close to full volumetric efficiency there. The ram effect obviously doing it's thing with a longer inlet. This is what John was talking about getting an improvement over wider range of RPM.

With more testing to come we will obviously see and get more information. I would like to see the same test done with heads that have had the ports finished to remove the rough casting surface.  

Grizzly (Aussie Mainline)