1. Oil sump (or simply sump)
2. Bearings (integrated in a bedplate on the Honda S 2000)
3. Engine block
7. Rods (or connecting rods)
8. Head gasket
9. Pistons cooling jets (sometimes)
10. Clutch disc and pressure plate
11. Cylinder head bolts
12. Camshafts bearings
14. Rockers levers assembly
15. Timing chain and gears
16. Valves and valve springs
18. Cylinder head
19. Intake manifold
20. Windage tray
21. Ignition coils.
Those three engines show quite a few differences. The upper ones are 4 cylinders in line, the one below is a V8. The Honda has 4 valves per cylinders while the others have 2. The valves of the Honda are opened by rockers whereas they are actuated directly by inverted lifters-cups on the Alfa-Romeo and via lifters, pushrods and rockers on V8 Chevrolet big-block which has only one central camshaft.
Tested on some NASCAR racing cars in 1963, it was officially disclosed in 1965 in 6.5 liters (396 cubic inches), then later in 7 liters (427 CI) and 7.5 liters (454 CI). Light alloy versions finally reaching 510 cubic inches (8.4 liters) dominated the Can-Am races and it remains a favorite engine amongst US racers. A 8.1 liters version is still in production (L18). Thanks to innovative stud mounted rockers arms, its valves could be slanted on both transverse and longitudinal planes as well, so that it was nicknamed "Porcupine", or alternatively "Rat". It was featured on the front page of the 1965-66 Automotive special edition of the French magazine "Science et Vie".
The Alfa-Romeo, with double overhead camshaft (DOHC), block, cylinder head and casings out of aluminum was designed according to the typical architecture of the European race engines of the era. It appeared in 1954 on the Giulietta Sprint with 1290 cc (bore74 mm and stroke75 mm). A version of 1570 cc (78 x 82mm) was marketed in 1962 for the Giulia and then another one of 80 x 88.5 per 1779 cc followed. On the "75 Turbo" it was equipped with a turbocharger. The final 2 liters version shown above was produced till 1993 with 84 mm bore. It received an indirect injection equipment and even a timing variator on the intake camshaft, quite visible on the drawing.
The Honda F 20C of the S 2000 VTEC of 87 x 84 mm offers the performances of a real race engine thanks to its variable valve timing, lift and duration: 241 hp at 8300 rpm, (120 hp/liter) along with a maximum rpm of 9000 for a Formula 1 like mean piston speed of 25 m/sec! Its sophistication contrasts with the rusticity of the "big block" Chevrolet, even if all the parts of the latter are not represented on the photograph.