Sorry to say but this is almost certainly not going to work. It's not about just diameter but also centre line. You might be VERY lucky in that both cases might have the same centre line, but you need to check this meticulously, and then you have the PIA of organising 2 sets of bearings. Which are sold in pairs of course. A possible solution would be to measure how much offset you have and then correct it by machining new dowel holes but oversize (a couple of thou). Obviously a job for a competent machine shop, but cheaper than a new block. I learnt this the hard way when trying to use camshaft holders from another cylinder head. It ran fine for 5 minutes, long enough for me to get a mile down the road before the inlet cam seized and wrecked the entire head.