What would you do?

The early A v8 manifolds are the worst. Worse than the big block ones IMO and those are pretty bad... So if you wnt manifolds I'd just build the 273. If you are thinking bigger the 340 HP manifolds from teh 68-71s will fit and flow much better. Not sure about teh 72s but I think the only difference is the size of the outlets - on the 72 they are 2" rather than 2 1/4".