I want to raise my trailer a few inch's my leaf springs are already on top of the axle is blocks the answer to get it higher, already lowered the hitch to max bed to trailer height.
None of the axle manufacturers offer blocks for lifting nor do they recommend them. Nor do trailer manufacturers offer the option in a multi axle trailer. Main reason is side stress issues from sliding sideways around corners add lots of stress to the Ubolts and spring keepers.
As mentioned the sub frame is a better option or heavy plate spring hangers with adjustable holes like many newer RV come OEM with.