With the (68hp) Lexus MGR I calculated the weight of the engine, transmission, gas tank, shift rod, etc. would offset the (98lb) weight of the MGR and battery pack.
As a hybrid, the pulley drive would have to be doubled up or substituted a
Gilmer belt drive like they use on superchargers.
As a pure EV, you might have a motor per wheel hub, with a 6 or 7:1 ratio.