Carl, where do you source 430 domed pistons?
Henry, you're beginning to find out how hard this engine is to properly overhaul. Name-brand parts MUST be available for a quality overhaul, and why not? Other engines have great support.
Unfortunately, the 430 is too rare for vendors to dedicate replacement parts shelf space. Every year, fewer are rebuilt.
The short block kit you show is for a 350 Chevy. They have a disclaimer, "Engine kit image is for illustrative purposes only." For SIX HUNDRED bucks, they should show correct parts. These are not, and If I lived in Australia I would NOT take the chance. All these parts should normally cost half and then you are at their mercy regarding brands.
Don't feel bad, 430 block thermostats cannot be found anywhere. No, the 'universal thermostat' you show will not work in a 430. Diverters are supposed to upset the coolant flow to make better contact with cylinder walls. They do not regulate engine heat. When original thermostats go bad the only choice is to do without. That's why it's widely accepted.
"Domed pistons for the 430 MEL are 'custom made' only."
Make no mistake, this doesn't mean they are available. It means, IF you can find a piston maker, he must have lead time to cast 430 domed pistons. Again, four are RH and four are LH. They must be large enough to fit a newly bored block. What's the cost? Contact the foundry.
Building a 430 is so daunting, most rebuilders 'settle' for common flat top pistons that totally ruin the original compression ratio. Egge.com was a popular supplier of wrong parts that 'work' but now they don't touch 430s. My observation is, most 'rebuilt' 430 engines get sold, then the new owners ask why 400-HP just isn't there.
I normally don't refer our members to another board but in your case, CLICK HERE.
I wish my suggestions were more favorable but I am looking out for your best interest by steering you in the right direction. I still stick to my prior posts/advice. Bottom line is, it's your money and your car to do with what you please. Good luck. - Dave