3/8 10 degree single square groove, Comp Cams 612-8 or 612-16.
3/8 10 degree 8 or 16 Chrysler 2-groove Comp Cams 625-8 or 625-16.
3/8 10 degree 8-ea 2-groove and 8-ea 4-groove Comp Cams 627-16.
The 995 spring will use a Comp Cams 740-16 10 degree retainer and you must machine the spring seat in the head to accommodate the dual spring. To do this you could use Comp Cams spring seat cutter 4719 and Comp Cams 3/8 arbor for seat/valve guide cutters, 4734. Then you would need to use valve guide cutter 4726 and 3/8 valve seals 515-16. Make sure you cut the valve guide height down enough so that the retainers do not hit the seal/guide at full lift.
If you try to drill out the guides for bronze liners, you will have one hell of a mess that only a machinist can repair. It takes special tools to do it correctly.
I admire your courage but I fear this project will.............ah.........bite y...........ah............be a disappo..............ah.........have a HUGH learning curve.