I think I agree with Danny although I don't know where you are. My 122 wagon
has the aluminum manifold and my 164 has the combined cast arn manifold. When
the 122 gets warm it is excellent but it only warms up quickly if I drive it
a mile or so and park it for a few minutes (for heat conduction because of the
cooling effect of vaporizing the incoming gasoline). Otherwise I have to drive
it for 5 miles or so before it acts right and practically nothing I drive to
is that far away. (Small towns are really nice!) The 164 is tractable within
one block. I went to aluminum manifolds while I was in Panama where it is
always either warm or hot and they were great there and are fine here in the
summer, but if it is much below freezing the cast arn combined manifold is
a better deal unless you are going for all out power, maybe with bigger
carbs. A little work making sure the manifold interior is smooth and that
the ports match would be a good investment.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma