The '1600' Transporter was last imported in 1971, and that engine made 60hp (SAE gross) or about 46hp (SAE net, which is what we go by today). And while the 1.6L continued as a standard engine in other markets well into the '80s, we never saw them again. 1971 was also the last year we saw commercial type Transporters here (thank you, Chicken Tax
).
In 1972, the 1.7L Type 4 engine (from the 411/914) was fitted to all US-bound T2s, and it made 63hp net. A year later, a bump to 1.8L (went to a little larger bore, but still had the 66mm stroke which was why these engines were rather torqueless down low compared to the 1.6L with a 69mm stroke). In 1975, as well as 1974 CA/automatic T2s, they added Bosch L-jet EFI thankfully to replace the troublesome twin carbs of the first Type 4 engines. Both twin carb and EFI 1.8L make 65hp net.
In 1976, they went ahead and placed a detuned version of the 2.0L Type 4 engine, from the 914 2.0, in the T2. It only made 67hp, but with its signifigantly longer stroke had considerably more low end torque, with a peak of 105. However, the tiny valves placed in the heads (vs. the giant ones in the 914 as well as 912E) kept its revs lower. The 914 2.0 made 85hp thanks to those bigger valves, different higher compression pistons, and a different camshaft. But that engine also never had to move a box through the air
.
In 1978, they added hydraulic lifters for export models (USA/Canada) as well as some other markets. The Transporter engine of choice in Germany was still the 1.6L. In 1979, they changed the exhaust ports on the heads, which meant the entire exhaust system was a little different, and since in 1980 the T3 came out, which was totally different again, it made the 1979 exhaust parts unique and quite expensive.
The T3 (called the 'Vanagon' here, for van-wagon) used a modified 2.0L Type 4 engine still making 67hp, and they sold that here through the first 4 months of the 1983 model year, then giving way to the 87hp 1.9L "waterboxer" engine (another story). The T3 was also available with a diesel, but that was only sold here from 1981 through 1983, and is essentially a detuned 1.6L diesel engine from the FWD cars, layed on its side, making 48hp (yeah, THOSE are slow).
My 2.0L 1982 Vanagon can cruise comfortably at 70 MPH all day long, and can be asked to go to 80 if needed to pass someone but I rarely push it that hard. It does lose some steam on the hills, but I have used it frequently to tow cars and carry some really heavy loads (stuff that would bend a Sienna in half). Of course, I have done a few mods to its engine when I overhauled it a few years ago, but it still probably only makes 80hp or so.
The only "issue" with it is that it has no air conditioner, it never had it, and even when they did it was just a lame added on thing that was not very good anyways. Got great heat so long as you are moving, though, and is the nicer GL trim level with 2-tone paint, velour seats with inlays in the doors, etc.