I would say it would be better to do both.
But if only one choice,then do just the head,,,, but need to open up the intake port window quite a bit for the head to flow OK.
I personally have just devided an intake manifold,it helps also.
http://i87.photobucket.com/albums/k148/itsjustasix/Img_1002.jpg


Intake gasket mating surface gets thin.Be carefull!
Look @ this thread: https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=43253&fpart=16
,5th post down for pics.

I would be hesitant to devide both for all out HP, but for a driver ,more even A/F mixtures to each cyl & not too worried about making the most HP it would be OK.


MBHD

12 port SDS EFI