Usually by bolts to the back of the block in the same positions as the proper flywheel cover, but it may need longer bolts or flatter heads. It may need studs or bolts of different length or thread from vehicle originals. Series I owners. Welded are best, and need easy access to the mount studs for those many engine mounts you are going to have to replace due to added torque and oil-spray effects. The cogniscenti swear by 186 or 179, claiming the 202 gets holed pistons more easily.
Problems here can be a cause of premature engine death and massive fuel consumption.
A major warning is that the adaptor must be centred properly since the gearbox and clutch esp' will wear dramatically if the input shaft does not run true. You can check this using flywheel run-out dial gauge measurements at different positions around adaptor. In the USA there is a different family of adaptors, for USA engines. In South Africa we used to put Chev V6 2.5 up to 4.1 L in, went very well, small motor and lots of space to get in. This involves a chassis cut if the radiator is deep.