On regular bearings, I heat the crankcase halves to 320° in the bearing pocket with a mapp gas torch. Mapp bottles hook up just like the propane bottles, but burns a little hotter.
A good $20 investment is a digital laser instant "spot temperature" reading gun. They read in either celcius or farenheit. https://www.amazon.com/gp/aw/d/B00D...+heat+gun&dpPl=1&dpID=41rSctD2mHL&ref=plSrch#
They are cheap, and help you be sure it's expanded enough to drop the bearing right in with no guesswork and frantic cussing when your expensive bearing stops halfway in.