LS Engine COnversion Plate bolts

[RJT-Maro]

I purchased StainlessWorks headers for my 1980 Camaro Z28 that I'm putting an LS 5.3 engine in. It came with the 1" setback plates but NO bolts to bolt the plate to the block. Two of the bolts are headed bolts and two go in countersunk holes and have countersunk bolt heads. Can anyone tell me the size/specs on these bolts? I called SW and they don't seel the bolts for the plates that were included. I have a Fastenal where I live and figure I can get the bolts from them if I know the bolt size/specs. Any help would be appreciated!