Well going off EGT (Exhaust Gas Temperature) gauge info here's the low down. The EGT would always be slighty hotter that the parts. This is with an engine at full song over a 1/4 mile. The EGT probes take the temp of the header pipe just as it exits the port.
Carby/Petrol = 1300-1400*F (704-760*C)
Carby/Methanol = 1200-1300*F (649-704*C)
Injected/Methanol = 1100-1200*F (593-649*C)
Going off the info I have, several souces quote different temps for propane burning
..........Propane burns at 2800-3500*F (1537-1977*C). So I would deduce, you could be OK! The higher figures are possibly with an oxgen mix tank to get it hotter. Just don't breathe your exhaust gas!!