I'd get those head gaskets done now !
Even if you intend on doing more work in the future. Just put the heads you are using now back on for the time being.
It's a pretty straight forward job and you can check out a few things in preparation for your big rebuild such as bolting your new headers to the edelbrock heads and you can have a look at the bores and see what the cylinder wear is like. You may ultimately need to build a whole motor not just put the Edelbrock heads on what you've got.
Don't use the old rocker arms off your original heads, i'd say they are stuffed by now. Maybe get some roller rockers.
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