[2] Bullock married physiotherapist and fellow UQ graduate Margaret Roberts in 1957 and they moved to Boston, USA to take up a Fulbright Fellowship he was offered at Harvard University.
[2] Bullock pursued research in a number of areas including hybrid and electric transmissions for cars[5] and heavy duty road vehicles to reduce fuel usage and emissions.
In the 1970s he pioneered research into hybrid vehicles, converting a Ford Falcon to run on a small internal combustion engine with battery and flywheel energy storage, with Dr Duncan Gilmore.
[6] He and Dr Frank Grigg, worked on a re-design of power trains used in underground load haul dump vehicles.
[2][7] Bullock retired from the university in 1991 and continued in private work for Transport Energy Systems,[8] a company which he established the same year.