hey
i liv in sa! i had a ke30 rolla with a 2tgeu in it(1600 twin cam efi very old jap motor) i was selling it and the guy wonted the right engine #. on the rego papers! so i rang up regency! there is a modification #. I can get it if you cant find it im sure its in the white pages! (or ask motor reg.
they told me i could go from a 1176cc to a 1587cc or somthing around the mark as long as it was leaded! yes i ran premeum in it but it was such an old motor that they belived me when i filled out the form as leaded!
all you have to do is ring them and find out exactly wot you can do (without having to go to the parks and get it checked!) and go to motor reg. get the form ! its the same form as if you were just changing the motor cos the old one died!!
i did all this and they just sent me a new sticker with the right eng. #. on it!!! Sweet!

Note the guys on the phone on the modification #. are usually F*#K heads just be blunt they have just about every motor on file so they can find out! its just a matter of them looking!! and dont hang up till your sure you got everything you wont! and get there name if posible so if somethings wrong you know who to blame and abuse!!

lastly when you ask them about your questions say " I PLAN TO PUT THIS A15 IN MY 1200" not "IVE PUT THIS A15 IN MY 1200" you get the drift!!!
let us know how you go!!
or if there is anything i can help you with!!

good luck!