Someone either lied to you or didn't have a clue about that motor. I have pop ups in my 5.0 with Twisted Wedge heads and I'm only at 10:1. If that really is the cam, that sounds too radical to put on a street car. Not only long tubes, but a 4:56 gear to get it up in the torque curve quicker too.
I'd start asking for receipts of the build or photos of pistons, etc...
The later 302's, AKA: 5.0 is known as the HO for High Output, but the only HiPo Ford ever produced was the 289.
Sounds like you have a good plan on the suspension though.
1966 GT Fastback, restoration almost there! Code T Red with White LeMans stripes.
2015 GT Fastback - Deep Impact Blue