Does anyone know what size these need to be? Online it looks like they're supposed to be 10mm. Can i just use grade 8 bolts, or do I need special bolts? I reason why I ask is that the ones online are all 1.5" long and I think I really only need something that is .5" long or .75" long max.

they need to be 10mm (dia) x 1.5 (pitch) . . . the 1.5 does not refer to inches it refers to the thread pitch in (mm)

thanks! the summit page confused me:
http://www.summitracing.com/parts/ARP-230-7304/Application/?prefilter=1

Torque Converter Bolts, 10mm x 1.5 in.,

Can I just buy some grade 8 bolts?

Stock torque converter?
10m - 1.50 X 15mm
(10mm diameter - 1.5 thread per mm thread pitch x 15mm long
I would stick with a washer headed bolt & locktite, not a fan of flat washer on torque converters.
Make sure bolt won't bottom out on converter!!!

Actually - 1.5mm per thread . . . gotta keep those specs accurate!