For the past year, I have been watching jehugarcia on youtube. He created his own DIY VW Bus into an electric vehicle. He built his own batteries packs as well as taking on the task of transforming his VW bus.
He is amazing and has inspired me. I would love to transform an old classic into car or pickup truck to EV.
They do make kits for some popular cars. The VW Beatle is the most popular as far as I can tell. Also, a lot of hot rodders are starting to beat gas engines on the track.
I currently have a 1957 Chevy 3100 with 350 TBI.
At Sema 2016 they showed a bolt on hybrid that converts conventional gas engines.
I would love to bolt this into my 1957. I sent them an email, they said they still under development. They took my email and said they contact me in the future when it was ready. They said the price would be about $5000.
check it out the link E-Charger website