Show your Slant 6 engines!

May I jump in on your question? The Clifford intake is not quite as street friendly as the Offy - more of a race orientated manifold with no provisions for exhaust heat. Yes, there is a water sandwich plate that coolant via the heater hose warms the manifold. And yes, the Clifford requires you to run headers. You mention adding them to a stock engine - without raising the CR by either decking the block and/or cutting the head, head work (port work/OS valves), cam, etc, - you will be disappointed in the performance. I did the just the Clifford intake and headers to my stock 65 Dart way back in 84 and although the exhaust sounded good, the performance hardly increased.

Am doing it a lot different with my wagon this time- block decked 90 thou, head cut at least 10 thou, mild port/polish, 1.70/1.44 oversize valves, 340 valve springs and depending on head gasket thickness will run a CR of 9.4 to 9.7. The cam is pretty stout to take advantage of the mods. I will use my Offy 4 barrel and if I need more, I'll go to my Dutra Hyperpak. I plan on running the FiTech injection. Long tube headers will take care of the exhaust.

Good luck whichever way you go!