Dimensions of an uncut Edelbrock head

[jayb]

I'm putting together a dummy FE to use as a fitment check for the FE intake adapter I'm working on.  This mockup engine is going to use a 390 block that has been decked and squared, with thicker than stock head gaskets so that the top surface of the head gasket will be the same as a stock deck height FE (10.170") plus a standard head gasket (.040").  Topping off the block I will be using a set of Edelbrock heads, since they are a very popular aftermarket accessory.  I want to use a set of heads that has not been cut.  I have three sets of Ed heads here, but unfortunately I can't remember if any of them are not cut. 

In order to figure this out I'd like to know the depth of the oil transfer slot on an uncut Edelbrock head, to see if any of the heads I have are as delivered from Edelbrock.  If anyone has a set of uncut Edelbrock heads off an engine and could measure this for me I'd appreciate it.  The photos below show the oil transfer slot I'm talking about, and also how to measure it using a dial caliper.  Thanks in advance for any help on this - Jay

[XR7]

Hi Jay, glad to see you working on this project!

I have a set of what I believe are un-cut ED heads here, plus a set of heads I know were un-cut... then I ported and cut them .030".

The un-cut heads measure about .180 and the cut heads were around .150 so this must be pretty close. The oil slot is cut with a ball end-mill and my calipers have a bit of a small square end... so it is hard to measure perfect.

I think a lot of blocks end up around 10.150 to 10.155 or so once they have been square decked ,even new blocks get cut to around this dimension since most of the new stroker piston etc. have pin heights to put them down the hole around .005 to zero deck or so, with these dimensions. Not sure if building this set-up for 10.170 would be best... but somewhere in between possibly as a guy can always mill a little here and there on heads and "adapter manifold" or any other manifold to get things where they needed to be.

[jayb]

Thanks Thor, I'm measuring 0.185" with my caliper on the heads that I suspect are not cut, so it sounds like if they have been cut, it hasn't been much.  We'll see if anyone else can provide some confirming data.

On the block deck height issue the aftermarket blocks are all 10.15" as far as I know, but I do have a couple factory blocks that measure the stock 10.17" value.  I don't want to make the manifold so that it will sit too low on a factory spec block; I'd rather make it so it could be cut to fit a lower deck block if necessary.  I think I will measure an Edelbrock Performer RPM intake before I finalize this decision, though.  The good news is that I can adjust the mockup with different head gasket thicknesses, so I can end up wherever I decide I need to be.

[Joe-jdc]

RPM heads stock:  Jay I have 4 sets of Edelbrock heads that are new, and they are all different.  One very old set from mid 90's measures .167", one .178", one  .185", and a new set just received a few weeks ago, .200".  I would measure the bottom of the port from Edelbrock, but all of mine have been modified there, already.  Joe-JDC.

[jayb]

Thanks Joe, sounds like the deck to oil slot measurement may not be the best place to determine if the deck has been cut.  Does anyone else have the dimension from the bottom of the port to the deck on an uncut set of Edelbrocks?

[Joe-jdc]

Jay,  I checked the deck to the head bolt holes on 3 heads, and it was 3.420" on all three heads from different pairs.  On the intake face side of the head, measure from deck to head bolt holes on the three that are easy to get to.  Seems to be a reliable spot to check.  Joe-JDC.

[jayb]

Thanks Joe, I checked the pair of my heads for this dimension and got 3.420", 3.415", and 3.410" on the three head bolt bosses that were easy to measure, on one of the heads.  The other head measures 3.410" all the way across.  I think they must have been cut, or not right from Edelbrock.  Looks like I might be getting a new set of Edelbrocks for mockup purposes...