KZ750 shim under bucket into 77 KZ1000 for Big Cam

Anyone can help me that question? Can I use the set of shim under bucket from 1980-81 KZ750 into my 1977 KZ1000 for a high lift cam with 0.430 lift?

it is not a great idea to use the 650 or 750 buckets on big lift cams with heavy valve springs as they can actually break i have seen it happen that being said i have used them myself before on street motors and got away with it but motors cost so much nowadays i don't think i would trust them myself any more

yes you can. 0.430 is not so heavy...
but you need different springs because of the more compression

Yes you can. I will caution you about using old used buckets with wear patterns. They can wreck a new set of cams. The cams and buckets transfer the wear patterns to each other. All cam companies will tell you to use new buckets with new cams.

They fit, but were known to wear rapidly if valve spring pressure was increase over stock

What do the after market springs do from APE? Are they tougher then stock or just thinner to let the spring being more compressed??

They both have more pressure and stack shorter to accommodate more lift.

Jay