Four-cylinder, 2000cc Alfa Romeo cylinder heads are somewhat interchangeable, but it's important to know the differences. The following comments refer to the photos above and below:Figure A shows the location of rear oil drain-back holes in the SPICA heads and in early Bosch L-Jetronic heads. During the late 1980's, Alfa must have determined that these were not desirable, and deleted them (also see fig. D). Head gaskets have a provision for these holes, and these work fine on the newer engines, too (note that the Motronic head had no holes; the outline is from the gasket). Fig. B shows that Bosch-injected cars, both L-Jetronic and Motronic, have additional injection cutouts in the intake ports. Otherwise, the port spacing and bolt pattern is the same as the SPICA head. Fig. C shows a meaty boss that is present on the intake side of late L-Jet and Motronic heads. I have had to grind this off to install a European intake manifold onto a late Bosch head. Fig. D refers to the drain-down slots under the cam covers on SPICA and early Bosch heads. Again, these were deleted on later cars (the oil drained only from holes in the timing cavity). Cam covers seem to fit interchangeably with respect to these slots. Fig. E is a boss we see on Motronic heads. I don't know what it was for. Fig. F indicates that Motronic heads differ from all others by having visibly lower tappet bores on the intake side. If you look carefully, you will see that the surface machined for the cam cover reaches the tappet bores; on the Motronic it does not. This is because the Motronic camshafts have a slightly larger lobe circle. See also Identifying 2-liter Alfa Pistons. - Mark Lee
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