Front "China wall" sealing issue on SBM

toolmanmike said
I would contact the manufacturer and show them what's up. With that design you aren't the only one with the issue. Possibly they caught the issue and made a production change to correct it. You could have bought a early manifold.

416stroker said he contacted Edelbrock when he figured out the issue, they said they'd pass it on to their engineers and mold makers but who's to say they actually did it. If they did I don't know if my manifold was made before or after the fix as I bought it used off schmeeBay, likely before since I'm having the issue...

Dale Davies said
Are you certain it is the china rail leaking? When installing the machined intake, verify the fit before torquing with a feeler gauge. Any gap should be identical top and bottom. The coolant can still seal because of the printed sealant or embossing, but still seep out just above the head gasket. Could the head gasket be leaking slightly in that thin area by the pushrods?

I'm about 95% certain. I've looked up at it from underneath with a good flashlight and the oil is coming from that corner interface between head, intake and block. The intake faces were also milled and the edges were all left sharp so they "dig" nicely into the intake gaskets when the bolts are torqued down. Last time I resealed it that corner stayed dry for a few drives then came back; if it was the head gasket the leak would still have been there. Not to mention I'm running custom-thickness Cometics with head studs, damn things better not leak! lol