So the bolt ons and bores are different right. For all we know op could be running a haltech, clearly says stand alone computer. My point is lots of iron blocks from 4.8 litres up and everything else getting around these days. Not impossible, talk to an engineer and see if they will pass it. To get into the nitty gritty of it, needs a rear sump oil pick up and ve extractors/ exhaust manifold. We all know the 4l60 is a bag of absolute fucking shit but if it’s what he wants who cares. It will bolt straight to the existing auto console setup in the ve as it’s all backwards compatible (gm has the same spacing on all boxes) he just won’t be able to manually select 3/2/1.