Upgrading a 17080565 (marine) to 17080561 (marine) specs

[latte114]

I have two 17080565 marine QJs and would like to upgrade them to 17080561 specs.  The 17080565s came off 228HP 305 CID Mercruiser V8s. The 17080561 came off a '85 260HP 350 CID Mercruiser V8.  The 305s are gone but I have several 350 CID engines in mid 80s boats and I'd like to have a couple of carbs as backup.  What would I need to make this happen?

[Cliff Ruggles]

I would rebuild them with our Marine rebuild kits, and we can also supply jets and metering rods as well to get them on par for the 350 engines.  We're here 8am-4pm, M-F EST...tks...Cliff