therer are only a few cases that can be machined to the desiered size the rest are junk, (case clearence for the crank, and cut the case for the pistons and sleaves) i suggest you to go to
http://www.reliablevdub.com/ talk to
Troy, he can awnser any and all quetions about
classic vw motors, he rebuilds them has been doing it for over 30 years, that being said were in Dallas TX dont know how mutch help othere than advice can be given but you never know, and he could tell you exactly what you need to do with the buget you have and hp goal, some of the best vw bug drag racers of the US tend to hang out on his site for mon. night chat so some one ther can awnser any quetion you may have, i dont know if he will ship that far lol, but he may , or he may know some one your way, you never know
you could also go to the samba, but most of the people there are jerkes in the forum, but a good place for buying parts
1300cc, is not realy good for any thing not many places can line bore it for a rebuild, (plus it is a single port, you need a dule,) at least not here in the US, i have a 1970 may be the difrenc of the contry but i thought thay were 1600cc, is that the motor that came in it
that being said he is curently building me my seconed motor for my bug, 1600cc now going to 1835cc, had the money, remember befor you up the motor get steering, brakes, done first, make it safe at least front disc convertion, then due trans, big motor is no good if it kills your trans, Carl on the same site is building me a trans too, hopfuly it will all be done end of this month, good luck with your car, hope this helps you