I asked Rick Ehrenberg of Mopar Action the same question about the 68 340 4 speed cam and he said go with a modern fast rate cam for more power and streetability instead of a 45 year old grind.
I was looking at the Comp Cams XE268H which is their modern fast ramp rate grind which is the biggest cam possible in the XE line with the factory valve springs.
What cam did you go with?
