Dont see how...
I mean i did a JUN 2.2 kit on my second GTS-X and the crank was totally different to a stock rb26 one...
I just dont see it turning in that little bore. I mean the counter waits...
I dont think the rb26 bearing will fit the rb20 block in fact im sure they wont. Also you can't use the rb20 bearings as their smaller on the big ends....
Anyways by the time you get these parts you will have spent enough money to pay for a full JUN kit brand new...
I paid AUD $3400 for the kit when i was in japan on holidays.
The kit included pistons, crank, rods, bearings & rings.
I also purchased cams and other bits and pieces to suit at an extra cost.