The '716' heads are nice for correct restorations, but they're a dog performance-wise compared to any of the later heads.
The '092' heads aren't much better than the '716' heads other than the fact that they give you the ability to use the '65 and later intakes.
I would either rebuild what you have or get a set of '67 -'70 400 big-valve heads. Larger valves can be added to the #47s for not much more than the cost of new smaller valves and you can have a street-porting job done on them. A bowl clean-up and bigger valves along with a quality valve job would net you a nice relatively inexpensive flow increase.
Leave the old 389 heads for restorations, if you want more power you really don't want them.
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1964 Tempest Coupe LS3/4L70E/3.42
1964 Le Mans Convertible 421 HO/TH350/3.08
2002 WS6 Convertible LS1/4L60E/3.23
1966 VW Type 2 Single Cab Pickup 140hp 2276
1956 VW Type 2 Panel Van 36hp 1200
1957 VW Type 1 Beetle 180hp 2276
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