That might be the culprit of the weak spark you had recently. The energy of the ls1 coils is too much for the platinum disks to handle on these plugs and the spark scatters taking the least resistance path around the platinum disk. I should say they are either defective or the ls1 coils are overkill for 41-906s. Tr55s are always better for non stock application, but they must be replaced quite often for optimal performance.

If your fuel pump can support 60psi and you have a regulator for 60psi, go for it. Much better spay pattern and atomization with the newer ls1 style injectors.