Here's some info courtesy of AirCooled.net:
The engine case is what holds everything together, so selection and preparation are critical. Use a new case. Simple. NO LINE BORED CASES. Line boring is a Band-Aid, and will most likely result in overheating and low oil pressure problems soon after the engine is built. Don't compromise, and use a new case. The used ones out there are worn out, and not up to the task, so just factor a new case and machining into your budget from the beginning. A quality machine shop (we can steer you to one) is capable of doing the required machine work to make an 82/84 X 94mm engine (2275/2332cc) a SLIP IN. You heard that right. I field questions all the time from people who want more performance, but who are hesitant or simply won't consider something larger than a 74mm stroke because they are afraid of "clearancing". When the parts arrive from the machine shop, or us, just clean 'em up, assemble the engine, make sure everything clears, and that's it. The mystery and concern regarding parts clearancing for large engines is overrated and a highly misunderstood part of performance engine assembly. 86 mm and longer strokes, however, do require more attention to assembly detail.Use 8mm head studs. New cases have case savers (Helicoils) built in, and these are far stronger than head studs threaded directly into the case. Use factory VW 8mm head studs (used are fine), since they expand and contract at the correct rate, and keep head torque constant. 10mm studs don't do this, and that's why 10mm stud engines have a problem with pulled studs.
John - AirCooled.Net