Generally speaking aluminum will, from a steady heat source, rise to temperature faster than cast iron. But the end temperature will not be any greater than the heat source. Because aluminum will reach terminal temperature faster, it will also dissipate heat faster when exposed to conductive or fluid cooling. So believe it or not, an aluminum manifold can raise the engine compartment temperature some what due to increased dissipation. Most vapor lock issues do not come from general heat source issues like engine compartments, (unless they are extreme) but direct heat sources. That is why your not having any issues because of your heat shield. Shielding from a direct source will almost always solve the problem. Earl Will an aluminum intake manifold heat the carburetor and fuel faster or slower than a cast iron manifold? BTW, Neither my car nor my friends have any vapor lock problems since we installed a fuel pump heat shield, as per Don Dulmage. Thanks, Don! Sean ---- Please address private mail -- mail of interest to only one person -- directly to that person. I.e., send parts/car transactions and negotiations as well as other personal messages only to the intended recipient, not to the Clubhouse public address. This practice will protect your privacy, reduce the total volume of mail and fine tune the content signal to Mopar topic. Thanks! '62 to '65 Mopar Clubhouse Discussion Guidelines: http://www.1962to1965mopar.ornocar.org/mletiq.html. ---- Please address private mail -- mail of interest to only one person -- directly to that person. I.e., send parts/car transactions and negotiations as well as other personal messages only to the intended recipient, not to the Clubhouse public address. This practice will protect your privacy, reduce the total volume of mail and fine tune the content signal to Mopar topic. Thanks! '62 to '65 Mopar Clubhouse Discussion Guidelines: http://www.1962to1965mopar.ornocar.org/mletiq.html.