Trik:

Sorry to rain on your parade, but the 60x engines are the "other breed" of diesels, those that have high mechanical compression and fairly low boost.

You are not going to find "low compression" pistons, and you also do not want to manufacture a set -- stock are $2500 a set. There are no, and are never going to be, aftermarket pistons for such low production number engines.

What you should think about is the fact that these engines produce quite a bit of horsepower on quite small displacements with very simple boost systems. You can up the boost and generate considerably more power (so long as you can also get more fuel!), but what for? My 300D does 0-60 in roughly 9 sec and goes 130 mph, and gets 31 mpg doing it (less if I floor it all the time). I did the math, and by displacement, the 603 turns out more hp and torque than a GM Vortec engine!

You trade high revs for that low compression, long stroke engine -- rev limit on the 60x engines is around 5000 rpm, and they will go faster at the expense of durability (normally 500,000 miles and more on the bottom end -- in fact, other than the bent rod problem in the 3.5L, I've never heard of one failing short of being run out of oil!).

The 601 is a four cylinder, the 602 is a five cylinder, and the 603, 606, and 607 engines are sixes. Bore, stroke, and pistons are identical except for the non-turbo engines (no oil cooling passages in the pistons). Turbos have oil jets, non turbos don't, I believe. 606 and 607s are DOHC engines rather than SOHC, with the injection port in the center. Rods are common on all engines, I believe. Certainly the crank throw is the same.

Make sure you have an EGT gauge if you overboost, else you risk roasting something or melting the pistons!

Note that the different thickness head gaskets on the VW/Audi/Volvo engines are to compensate for piston projection above the block. If you have "tall" pistons, you cannot lower the compression by using a thicker gasket.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!