Yes its head porting that would improve mixture and flow.
I would try sending it to someone local or try it yourself
with some of the many thread avail on this topic.
Im not sure the inlet manifold you have would suit an oval
port head hence the suggestion to try and port the head you
have already. If you go this route youll find the valves are
already the largest factory sizes available as I remember and
if you wanted to go larger on the exhaust side you could go
cut down L16 ones which will improve things again.
It all depends on what round port head you have.

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