To insert or not to install inserts or case savers? All VW cases imported into the USA after 1972 come from the factory already equipped with factory inserts to use the 8mm stud kit. One word of caution; many suppliers sell or furnish the "cheapo" aftermarket head stud kits made out of a substance as bad as Limburger cheese (because they stink) and in doing so have given the 8mm stud kit an unwarranted bad knock of stretching or coming loose. I have used the "genuine VW" head stud kits absolutely trouble free since their inception in 1972 on engines up to 150 HP for daily driving. They are made of a special composition of alloy material and heat treat for the correct expansion and contraction rates of the air cooled engine. They have the perfect torque at all operating temperatures the engine is made to run within. I, personally, would not use for street use, special chrome moly or cheapo studs, as they do not have the proper expansion rates.
The cheapo ones will stretch and the chrome moly have "0" stretch, so after being hot several times they often let the torque relax when cold and the heads start to leak until they get up to operating temperature. Soon they simply leak all of the time. Some all out turbo charged race engines, or other applications of causing too high of piston pressures, may require the special chrome moly stud kits. However, this is a short term run engine and will likely require retorquing or rebuilding at regular intervals. Also, in a short period of time requiring resurfacing the heads and case where the cylinders will crush into them. No, I do not sell them.
Special heat treated chrome moly head studs will be mandatory for some race applications with large bores. They may also be needed for long stroke, low compression street motors with very thick cylinder spacers that require a longer than stock stud. In some cases 8mm can be used and in other applications 10mm. We can furnish any of the chrome moly studs you require, please inquire.
Note: When the proper parts and procedures are used, and torqued to the correct torque on installation, no need to retorque the heads again after break in is ever needed.