Attaching a Rotisserie

I have a 69 barracuda on one right know. Its bolted on where the bumpers where. I guess you know you have to offset the pivot up to ballance it.It would be better bottom heavy than top. I will dig up some pitchers and offset measurements for you.I use a cumalong for a hold back to prevent an overhall. once you establish ballance you can take it off if you want.