you make peak torque at 0 RPM and a 500HP electric motor weighs about 130lbs.
I'm curious. What was your setup? What batteries did you use, how much did they way, and where were they in the car? I know the batteries, especially if you go with lead, add enough extra weight to negate the lightness of the engine. The fact that you can put them where you want though really helps with controlling the weight distribution.
I gotta be honest. I think a 5th Gen El Camino would be perfect for an electric car. Right behind the seat is a compartment called "smuggler's box" and it would be the perfect spot to store the batteries. It's close to the center of the car which would help out with the weight distribution while still allowing you to use the bed.