cylinder head swap

[Karly]

What are the differences (besides the exhaust ports) on the different year 2L cylinder heads? Are they interchangeable? I have the square ports on my motor, but I would like to swap them with some oval ports to run aftermarket header without the need for welding "stubbies" in.

[Karl]

Here are the differences between all the heads:
http://www.tunacan.net/t4/reference/cylhead.htm

[NeverHadaBeetle]

Good info at the tunacan website especially with regards to the valve sizes. If you have square port 2.0 liter heads then you need to find 1.8 heads from 1974-75 or 2.0 heads from 1976-78. The best year for performance was the dual carbed head on the 1974 bus. This head had the biggest valves of all the bus heads. The 2.0 liter 914 head had still larger valves, but was different in other ways also and they tend to be about twice the price of bus heads. If your square exhaust heads are stock 2.0 liter heads then they are cut for a 94mm cylinders and pistons. All 1.8 and 2.0 heads are cut for 94mm pistons and cylinders so any 1974-78 bus or 1.8 liter 914 head will work for you. The 1.7 heads (bus or 914) have smaller valves and need to be cut for the larger 94mm pistons and cylinders. Good luck.