We utilize a metal honeycomb pattern fascia to mimic the core pattern used in early Chevrolet radiators.  It has 1/4" depth and is 1/4" across the flats.  When placed against a 10 or 11FPI core it resembles the OE core pattern but without the cost. 

It will push the core back toward the core 1/4" but not encroach on the fans space.

You must design and construct a radiator to accommodate the fascia depth or it will not fit.