junkyard 360 magnum? big block?
My car is light (~2900 lbs), but I was pleasantly surprised by the performance of my budget Magnum engine. It's nothing fancy at all, just a stock long block, small cam (218/224, .506/.506), air-gap, block huggers, and a 650 dp. It ran pretty strong with a best time of 7.89 @ 90 mph, and that's with a stock lockup 904, including converter. The only modification to the trans was a TF-2 shift kit. You'll be happy with your choice to go Magnum.
...............and I just realized that everything in this post is listed in my signature. Oh well.