I'm running an LS3 with TR6060 and IRS. I need to fabricate an adapter for the transmission mount as the supplied mount was to suit a TKO. My understanding is that from a side view, the tranny should be pointing down at the same angle that the IRS pinion is pointing up (faces are parallel) so that the output speed remains constant as per the pic below:
11-driveshaft-alignment[1].jpg
The closest I can get is within 0.5 deg difference which I believe is acceptable. If I drop the tranny any further, I'll risk hitting the shaft on the chassis.

My question relates to alignment in the other plane - looking front to rear. It appears the IRS pinion is offset to the RHS by approx 20mm (3/4"), while the engine and tranny appear to be centered in the chassis. If I try and shift the tranny mount 20mm to the RHS, then the face of the output shaft is not parallel with the face of the IRS pinion. Am I better to keep the tranny mount centered so the output shaft face and IRS pinion face are parallel even though I'll end up with 20mm offset?