I also rang Yella Terra [03 9555 5522] & they advised that the 1.64 to 1 [not 1.65] ratio rockers were NLA, but would be available if i ordered 10 sets.
I too was quoted $834.95 tax paid, FOB at factory, but i was also advised that there was a price war between Rocket Industries in Sydney & a well known [but unrecalled] Melbourne outlet

I rang Rocket [02 8825 1900] & spoke to Nicholas, who said that the rocker kit was not a stocked item,[surprise] but he would get back to me,
He did. He quoted me $766.20, tax paid, FOB Sydney.
To this we must add any freight charges to send it to the customers home, plus a set of custom pushrods. [$220 seems a lot for eight pushrods, thats $27.50 each]

Perfectune Engineering / Yella Terra no longer make the pushrods & they sold all the manufacturing tooling to "Head Stud Development" in Melbourne, so either this company, or "Crow Cams" would be the source of the custom pushrods as they would need to be diferent lengths for the A10, A12, & A14/15 blocks.

So what are we up for. If you get any change from $1000 [Australian], you're laughing. For this you get.....

1 set of custom made pushrods, from the supplier of your choice.

I roller rocker kit, comprising, High strength alloy rocker arms that are claimed to be as much as 5 times the strength of stockers.
They have needle rollers for the main pivot, plus a roller tip.
The shaft is hardened for the rollers & is of a larger diameter than stock, which is why they provide the stands as well.
Oiling is provided in the normal way, but oil is fed to the individual rockers from the top of the shaft so that it will run down & lube ALL of the needles.

The adjusting screw is of a cup type which is the reason for the custom pushrods. I suspect that the screws are possibly Chevy ones as they are the most popular type of roller rocker that they make & using these screws saves a dollar in manufacture.

Only the 1.55 to 1 ratio is available, & even these would need to be made to customer order. If they can make 1.55 to 1 to order, then why not 1.64 to 1's?
Perhaps i will ring tomorrow & ask.