There are numerous threads (debates) in the archives about manifols heat. The main problem is fuel condensation (puddling) in the intake track. The heat will help keep the mixture atomized. Some people have had different results with maifold heat than others. It all depends on your application.

I use coolant plumbed to the bottom of the intake.
It seems to work fine, and cleared up a few issues for me. I have also run into fuel vaporization on one trip. Its was a hot day on a long trip. John


'68 C-10 - 250 with Edelbrock 600cfm 4 barrel, Offy intake, Hedman headers and true duals, HEI, MSD 6A box, relocated gas tank
Soon to have: T-5 tranny