>>>*The 20R head can be installed on the late low deck engine, it requires milling the head drastically to the same thickness as the later 1985 to 1995 design. This is to increase the compression ratio back to normal and so the later timing chain will fit.

Without milling, the 96 link chain is too short and the 98 link chain is too long.

Serious milling of course does also weaken the casting, although some do this with success I personally won't since I don't like crabby phone calls.

Also if you do try this, note of course the manifolds from the early engine also need to be used.

The combination is interesting in that the tiny round ports and small valves on the 20R react as high velocity ports, thus giving a nice snappy low end response.

If using the 1981 to 1984 22R head, note the much larger combustion chamber. That head will bolt on but note this would only work with a specialty type piston designed to increase the compression ratio, otherwise it will actually run but has very little power.......*EB