Heads/engine swap

Hey guysngals, been here forever but have not posted in a long time.
Preparing to remove the numbers motor in the fish and putting a 73 340 that has had some work done,pistons.,cam,valves?(not sure what is in there). Anyway this motor was chained down in the dart I got it from so I am thinking it is strong. What I am curious about are the heads. They are Z heads with the
casting number 3418915 under the valve cover. I have read previous threads from a few years back and I was wondering if anyone has new info on them. Seems to be the same or very similar to all the others (x, j and so on).
I have had a set of tti headers for quite a few years ready to go, looking forward to swapping , been lucky not to blow the original motor all these years. I think it should be straight forward swap but I am just wondering if there is anything else I should be aware of?...
Thanks
Sparky