TCL is correct (except on the Offy intakes - Cliffords have the water jackets).
The water heat won't help much on cold starting. That's the job of your choke or carb enrichment circuit. It's main value is constant gentle heat to prevent fuel "puddling" in a cold intake, which causes a lot of flat-spot symptoms and poor response. Tom Langdon's tech tip at
Inliners explains this much more eloquently than I can.
The early Datsun 240Z is one of the sweetest-running inlines ever produced - and uses a water-heated intake.
Since most multiple carb intakes and headers were derived from racing applications, intake heat was not provided. If you're running WOT all the time, you don't need it.
