Well, the 6" rod does improve the geometry a little bit, but the main point is that it costs a lot of money in both parts and labor to put a 292 crank into a 250 block, and probably makes it considerably more expensive than just using a 292 block to begin with. It would still be cheaper to ship a block from the US and build a 292 that way than to build one as a "stroker" using a 250 block. You need to start pricing machine work over there and see what it is going to cost to cut the counterweights down to clear the pistons and re-balance it afterward, along with the pistons and rods for the swap.
Its going to be cheaper to build a turbo 250. You can get many properly sized turbos off of eBay very reasonable, and you don't need any custom parts internally to do it.
