OK, Just had some time to get into the GMC intake stash. One is the same as the one pictured above. The two holes on top and the one center front are for vacuum. I have one for a bigger GMC(361,426,451,475) that is the same just huge. I have an Edmunds that has a 1/2" tube running length wise on the outer edge and is part of the casting. The Nicson & McGurk are exhaust heated like stock. Evidently Ellis used no heat. I have one for an International (k8,K10) with no heat and a 4 cylinder Ellis with no heat.
So, How to heat the one you are using. My 1st choice would be to drill holes in the flat ends and run a 1/2" tube through the log. It would take an aluminum tube and a TIG, maybe JB Weld. The more contact you can get with the manifold the more heat transfer you will get. 2nd choice might work better, run a 1/2" tube flush along the back side of the log between the intake on the engine side. This could be held with clamps that screw into the manifold. They may go through and have to be sealed. You will need to be sure that the water at one end has more pressure than the other so it will be constantly flowing, one end above the thermostat. Sorry no pictures.
Last edited by Beater of the Pack; 02/11/21 07:34 PM.
