Slow cranking

Just my opinion, but you'd probably save yourself some grief by putting the battery back up front.

I ran Mustangs a long time and that 50lbs isn't worth the hassle. If it's mounted in one of those plastic boat boxes, that would NEVER pass tech at the track, because as I recall it has to be in a sealed steel or aluminum box, vented to the outside of the car. And, I think you have to have a manual cutoff also.

I never liked the idea of a 15 foot live cable going through or under the car personally, but it's up to you.