Edelbrock combustion chamber

[475fetoploader]

Ok, I bought a comp cams cc kit. I’ve never used one, I’m not a professional anything.  I bought bare Edelbrock 60065 (I think) f.e. Heads. Now my original build idea, had a lot of compression So, I hand blended/cleaned up the chambers.  I bought Edelbrock valves, had the seats cut, sized the guides etc. I take my new comp cams cc kit, and start playing around. I did the first chamber twice, to see if I can at least do this well enough to get a repeat performance. So it’s 71 cc both times. I don’t believe the reading so I move to the next hole. It’s 70.6.  I thought these were 72cc, prior to me removing any material. I’m wondering what the forum has to offer from their experience with these heads. Thanks in advance.

[blykins]

It just depends on the valves that are used, how the valve job is done, etc.  I wouldn’t consider what you’re seeing is bad/wrong as long as you’re confident with how you set up your buret and your measurements.

[66FAIRLANE]

Its been a number of years since I ccd my Edelbrocks (purchased fully assembled) but I do remember they were larger than advertised.

[My427stang]

As Brent said, if the valves are sitting tall in the seats, spark plug differences, even how much you greased the edges and any that pushed in the chamber could be taking it away.

Did you do the other head?  No air bubbles?  If all that is good, it is what it is.




 

[475fetoploader]

I was thinking maybe Edelbrock sinks the seats farther. I used such a finite amount of grease, I cannot imagine anything false from that. Don’t get me wrong, if they’re going to come in around 71cc, it will be exactly where I was hoping to land. I’m just not used to being lucky, the first shot.

[plovett]

Mine are about 79cc.  I bought mine around 20 years ago, though. 

pl

[FrozenMerc]

The combustion chamber surface is as-cast on those heads as well.  Regular production tolerances will see that surface move around quite a bit in reference to the machined deck surface.  72 cc is probably at as-designed, nor nominal.  Every production piece will vary by some percentage from that nominal.  It is up to Edelbrock's QC department to hold the production parts within an acceptable range.

[Henrysnephew]

Gotta ask:  Did you buy the heads NEW?  Randy M

[475fetoploader]

Yes, bought them new, but bare.