EFI can help smooth out a big cam but even with EFI you'll want the cam to be down in the 230 range. The timing control in an EFI system allows you to put a lot of timing in at idle to smooth it out but then pull the timing as needed to keep from pinging. EFI also gives you better control over the AFR so you can easily dial in the idle mixture as well as off idle. But even EFI won't solve the bucking problem if the cam is too big for the combination. Modern cars solve it with variable cam timing but we don't have that option with the older engines.