LS1 vs. C5 Caliper

[ScotI]

I'm just doing a little research before accumulating parts to see if/what parts will work together. I'm trying to piece together a big-brake kit for a late model (79 Malibu) w/the PBR style calipers & a 13" x 1.25" C5 rotor w/o having to pay extra for 'Brand B'.

Is there any difference beyond the strengthening ribs?
Are the piston bores the same?
Are the caliper body widths the same?

I've heard these 2 are very similar. I want to use this style of caliper w/my 'already paid for' TT2's from a previous project but I'm concerned about the fit. I tried the wheels (18x8's) on our 02 TA & they fit just fine (~7/16" clearance).

Could I use the LS1 caliper on the 13" C5 rotor? Thanks!