That's a great story on the car, you have a great start going. Your drive train sounds a lot like mine in my 53 3100. I have a stock 5.3 tuned to 300 hp with a 4l60 trans, and 3.73 8.8. I have a mustang II rack and had leafs on the rear for just a bit before I went to a four link coil over set up. I highly recommend going to the coil overs in the rear right away, just for adjusting the ride height alone the're worth the extra money. With the 300 horse tune on my 140K 5.3, it has more than enough power and I'm averaging around 20-22 mpg. Yours is going to be a sweet right and I'm going to love seeing it come together!