in 'the old days' electric conversions often used jet engine starter motors. I dunno if they were getting them surplus or ????? They were about 20hp I think which should be good.
You only need about a dozen hp to move along at a decent clip. the xtra HP is for acceleration. A physics consultant where I worked (Serge Scherbatskoy) drove an old chevy pickup truck. He had a pendulum gadget that would 'capture' a mass at it's extreme deflection. Took it in the truck, did some runs in 2 directions, let off the gas at 55mph. After some calculations.... It only took 12hp to maintain 55mph. Electric motors give you full torque from 0 rpm so, 20hp electric would be a decent choice.
Or, maybe scavenge from a wrecked Nissan Leaf or Tesla? Some guy here in the States is using wrecked Tesla gear to electrify other chassis.