As in the title im looking for opinions on if still blocking the heat crossover is a plus or if anyone figured out it might keep more heat then wanted in the inner cylinders.
There is no benefit to blocking the intake manifold heating system on a
street-driven engine. The hot-spot under the carb is necessary to vaporize any fuel that falls out of the air stream and to replace the heat from the vaporizing fuel's cooling effect on the intake manifold. See the Carter, Holley, and Rochester references in
Intake Manifold Heat.
Even with an al. intake wont it heat sync nearly as hot sooner or later?
Nope. Without a working cross-over passage you won't have a hot-spot under the carb either.
