My 340 in my 66 developed issues :-(

Well, if it was that strong, Why mess with a good thing? To hear you extol the engine it sounds like an A-one combo.Too much more anything, may take it out of the realm of street-ability, and then the kids won't be willing to come along any more.
But I highly recommend to calculate the Scr, cuz this might happen again if the cylinder pressure is excessive.
And that combo looks to be pushing a lot of heat into the EGR port, and from there, it is cooking the oil under the intake,and probably cooking the carb too. Your manifolds/exhaust system are probably operating at their limit. I mean the evidence of the cooking is right there.
Ima thinking if you put any more power in her, you are gonna need some expensive supporting mods.