Thanks for the input, I'll definately have a squiz at it, I meant to last time I was home but ran out of time (my car lives in a different state for now although this will change when we move later this year).

I'm interseted but not sure what you mean by this

"That semicircular single bend radius is a good opportunity to put a slight angle on the throttle bodies which will give the opportunity to setup a prime approach angle of the runners as they lead into the ports. So imagine ¾ of a semicircle rather than exactly half a circle (well that’s the cheapest way anyway). Good idea."

, are you saying the input ports are angled and the runners should meet the head at an angle? I've never had it apart to look and it's the first Datsun I've ever owned, and probably the best looking small car there is in my opinion.

I've attached a draft of the design to give an idea of what I've got in mind. I was under the impression that the intake ports were directed more or less prependicularly from the manifold face.

Cheers

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  A15-CBR600-Mani.jpg (31.44 KB)