Offset valve spring retainers or keepers ?

And before you buy anything else..... let's look at that clearance to coil bind as you numbers don't look right:
1.65" installed - 1.100" coil bind = .550"
.550" - .480" valve lift = .070" clearance to coil bind

OK, makes more sense now!

Make sure the keeper grooves are the same shape as the valve groove (square or rounded).