[Dave at Pelican Parts]

The way they increased the stroke was to make the rod bearing journals smaller, and offset them toward the outside. In effect, they ground away the part of the crank that the rod rides on that "faces" the crank main bearings. This moves the center of rotation of the rod on the crank outward. A 2.5mm offset results in a 5mm increase in stroke.

They didn't increase the overall dimensions of anything that I know of. If you check the 914 catalog section of this page (Cylinder Head page), you'll find one listing for "push rods, 1970-1976 914-4 ALL". One length, all 914s.

The different-length pushrods generally come into play when you're monkeying around with valve train geometry.

So, yes. You can build your 1.7 out to 2.0 if you desire. I personally would start with a later 1.7 case (I think at least some of them came with the "windage tray" built in) or a 1.8 or 2.0 case.

Your car, your motor--your money.

--DD