EDIT: The link below from the BBC clearly posits the question of converting classic cars to electric drivetrains. If you are unhappy with that or found a link where 1 guy once made an electric Metro from a petrol Metro and you think no more can possibly be said on the subject, please move along.
I can't downvote yet, clearly many of you can, it's like reddit rebooted in here.
still editing: for all the people focussed purely on "now", think ahead 5-7 years. 2nd hand parts are common, development costs recovered, manufacturing costs in decline. Petrol harder to come by making a lot a of classic cars too expensive for the average car guy - now a conversion might be worth it in both time and bank.
Original post: From engineering and economic perspectives. Given that all existing cars have passed crash-tests etc and that the only real reason to go electric is environmental, does conversion make sense for many existing vehicles?
Inspiration for the question from here:
http://www.bbc.com/autos/story/20150521-vintage-gas-guzzlers-ripe-for-a-battery-powered-reboot