Not a bad idea Justinlonghorn. On the other hand, it can't be too hard to find a rack of those carbs or have they all vanished over the years?
I picked up a rack of K0 sandcast carbs a few years ago at Mid Ohio when the swap meet was at the fairgrounds or wherever it was. I needed them for a CB77 race project that never was finished. Time to shed more stuff I think.
Point being though that those carbs were not hard to find and I'm sure you can get a rack of spares somewhere.
CB750 carbs are super easy to find, especially through K6. K7 and K8 aren't hard either, but finding good sets can be more difficult. The bores on them wear out beyond use. The Pre-K7 are all over Ebay in $100 range and swaps have them for half that. The hardest thing to find when it comes to SOHC CB750s is the K7/K8 insulators. The aftermarket doesn't have good fitting sets, so they're prone to leaking, and the stock ones without cracks are rare.
There's a trick with the K7/K8 insulators, in that you can use 2x each of the two NOS parts that are available. Whichever ones you can still buy, you mount in the correct position. The other two can be rotated 180* over and function properly for the other two cylinders. Apparently Honda figured this out a long time ago, and instead of continuing to produce spares for each of the four cylinders, they only produced the insulators for two, as they are nearly identical once flipped over. Probably irrelevant to this thread but maybe useful to someone else.
Thanks folks. Yep, quite a few kicking around in the US, but not too many in Australia, let alone Tasmania (and postage from the US on them is a bit stupid)! But luckily I've found a set up in Queensland that look to have a good #1 body I can salvage and are winging their way to me as we type!