An ls3 can be stroked into 427, if you go lsx iron block your adding weight. You can do a ls3 427 with high compression, heads, big cam, victor intake with a dominator carb and make some crazy N/A power! I don't have any experience building a ls engine like that myself, my stuff was old school until now! I want to go 427 with mine down the road but keep it streetable.
217/228 .565 cam, th400 swap with 3600 stall, headers, GPI tune, VR intake, Bo white TB.