How to ID the block in my car

[poweredbyford]

Recently purchased an Aurora slabside Cobra and want to find out if it's the original motor. It's been worked by the past owner who owned an engine building/racing garage and don't know if he pulled the original and worked it or dropped another motor in.He was killed in a freak bike wreck two years ago and his widow has started to let go of some of his things from the shop including his cars and doesn't know anything about the history of how the car was set up which is bad for me so...while changing a leaky intake I came across some #,letters stamped at the back/top of the block DZ 658 58. Under the intake in the center of the block is a raised #80 and #3 with a raised XXX behind one of the lifter bores.

In theory the stock 1980ish 302 motors were sent to Holman&Moody to be warmed over before installation at the Aurora factory into the Cobras they built and this motor in its current state is anything but stock and it would be real nice to know what it is!

Thanks,

Dale