We fired the new 383" roller motor in my sons Nova tonight. Sounds great, except for the head to header leaks! One of the heads exhaust ports are taller than the other(same part #). He found a set of copper header gaskets that looked like they would take care of the difference. we have now found out that copper SBC header gasket don't seal at all. Has any one else had a similar problem with the Edelbrock heads? What gaskets work well? Any help would be appreciated. Thanks!
Some head bolts / studs will interfere with the flange on the header. Also some heads have 'raised' exhaust ports and you would need header designed for raised port to seal correctly.
The strange thing is that both heads purchased at the same time. Both boxes carry same part number. Didn't notice the slightly different port height until we went to use the Edelbock supplied header gaskets. Ports on one head are about 1/16" taller than ports on other head! Edelbrock said it shouldn't be a problem. They were told of the Dougs under the car headers he is using, again shouldn't be a problem. Their supplied gaskets were not going to work, so he went with the copper ones (not a good idea)! Any suggetions on other types of header gaskets? Thanks
I would get back with Edelbrock and say Now we have a problem and how are you going to fix it for me.
quick fix, get a set of flanges for the raised port, and run stock manifold gaskets in between. copper header gaskets only work where intended, no wiggle room of mismatched parts.
What about the numbers on the heads, do they match? It already is a problem for you. For what those heads cost I wouldn't want to "Jury Rig" anything! I'd do whatever it takes to get a matching set.
I had a problem on a 454 with large oval port heads. The exhaust ports would leak after awhile due to a mismatch between the port and header. I found some trim-to-fit exhaust biscuits at Earl's braided hose that worked great. After years of use, no header leaks.
If the entire port is just higher (same dimensions just higher compared to the bolt holes) I would just slot the bolt holes in the header flange and gaskets to align with the ports.
you can buy header gasket material and make your own gaskets, if your headers do not match your heads then whats that going to do to exhaust flow?, sounnds like your thinking 1/16" more sealing surface is going to make the difference between a good seal and no seal, i dont think so.
Personally on all the headers I have used over the last 15 or so years is 2 stock manifold gaskets stacked together. I have never had a leak at all. if they hold up to pressure and heat at 7000 rpms when I cross the stripe theyll hold on yours too. Good luck
1/16" core shift is pretty common, even in stock heads. That's why it's nice to port match heads, intakes and match the exhaust ports to the header gaskets. But that's not really necessary for what you're doing here. Are the exhaust ports on the Edelbrock heads stock size? If I understand your problem it's not port mismatch, but material. Am I right? For stock type ports I like Fel Pro Performance gasket 1426. They have gaskets for different sized and shaped ports too. Larry T
For what ever reason the exhaust ports on one head are aprox. 1/16" taller in height, than the other head. everything else is the same. The port size height is different from one head to the other!
So the 1/16" is enough to mismatch the header and the port? Are the headers round or square port? Larry T
i have the same problem with the big block i have this old guy i know said they used to used double gaskets to seal it up from felpro the steel high performance ones i dont know if it will work but i have to try somthing ...good luck
I am dancing this dance right now. My bet is you are using embossed gaskets. Embossed gaskets will not work unless perfectly matched. YOu need solid copper gaskets. Your gaskets will be on this page: http://www.scegaskets.com/Shop/Control/MainMenu/fp/tcat/257560/seo/1/sfv/32777/page/3/SFV/32777
Kev, if the ports are the same size top to bottom but one set is 'raised' on the head (or bolt holes are drilled low?) you really have two options. 1) call Edelbrock and see what they can do as far as sending you a head that will work properly as this one obviously is NG as is in your application. Unfortunately although this would be the best way in the long run, you need to pull the distributer, intake, valvetrain on one bank, drop the coolant, oil etc... PITA. 2) take the header off, elongate the holes downward the said 1/8 inch. You might be able to take some brake tube and cut to make half moon spacers to keep the header from dropping down over time. If their gasket does not cover the port properly, they really need to step up the plate to make good. If not I would definately seek help from the place of purchase. It would be a shame just to find some gasket to seal the leak but block 1/8 inch off each port. Defeats having better flowing heads if it all stops there. Joe
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