The manifold gets warm but the floor of the intake really needs to get hot to make sure the fuel atomizes. Otherwise it will puddle a little bit and you end up with a sloppy pig of a motor. So, I use the hot water method. I use to use no heat but many years ago now, I was sitting with Tom Langdon at the Carlisle swap meet and he persuaded me to give heat to the bottom of the intake a try.
And the truth is, Tom was still working as an engineer for GM, had a great deal of racing experience both on his own and for other big name folks, and every thing he ever advised me on was spot on. So I converted my Weiand intake to water heat and it ran better with the Carter YF carbs I was running at that time.
So I tend to be in the heat the intake corner, lol!
This is my Weiand intake. I ran this intake from 82 through 2017 or so when I switched to a Clifford 2X2 which has the hot water chamber cast into the intake.
If you look to the right of the intake, you can see my hot water plate.
My 20 something son is building a 261, and it’s a budget build, so I am resurrecting this intake set up for his motor.
GMC lower thermostat housing. They have ports on both sides of the housing, heater side and intake side.
