I bought the W2 heads used. The old Iron 810 castings. I was told they were ported by shady dell. I have no way of confirming that. I do have a set of W2 porting thempates and they fit perfectly.....
MP template ported should equal 300cfm up top but as said above by 33 IMP, flow test them. The reason being (from where I sit) is the head may not flow as much as the aluminum head and if your not lifting the valve up very high, then your not taking advantage of the cylinder heads air flow capability.
With the lift you mentioned above on the camshaft, that’s not a lot and the W2 loves a high lifting valve and even better if it hangs open there for a bit. Search YouTube for https://m.youtube.com/results?sp=mAEA&search_query=charlie+servidio
And scroll down some and find him (and I) flow testing my W2 heads.
Here is a W5 flow test where you can see stock vs ported W5 heads which are basically a square port aluminum version of the W2. They had very similar flow curves.
I have an old Crane SSH 320 cam that worked pretty well on an old 340 that closed @ 46 deg ABDC. 496" intake and 504" exhaust. I believe it was some where aroud 243 deg duration. I would probably look fr somethuing like that with maybe more lift.
Lift wise, get as much as possible with the W series head. Check every cam grinder you can find. Howard’s, Schneider cams, Bullet are a few of the smaller companies that are also very very good to check out.