Ram Air IV replaced the Ram Air II in 1969. It was called the Ram Air IV due to the planned use of four air inlets. Though production cars only got the two hood air inlets the name was retained. All 1968–69 #9792506 Ram Air 400 blocks have 4-bolt caps. The Ram Air IV used the Ram Air II's camshaft but lift in the Ram Air IV was increased to thanks to the use of 1.65 ratio rocker arms (vs 1.50). The Ram Air IV heads had 1/8" taller intake ports, larger intake port volume with more airflow, yet shared the Ram Air II round exhaust ports. In addition, a shallower spherical-wedge combustion chamber moved the tuliped valve heads .040" closer to the piston at TDC, improving mixture draw considerably during the intake stroke. The Ram Air IV also used a lightweight aluminum intake-manifold that produced a weight savings of . From 1969 though 1970, the Ram Air IV was available in both A-Body (GTO, including Judge) and F-body (Firebird, including Trans Am) form. While production of 1969–70 A-body Ram Air IV cars was low at just 1563 units(759 1969 GTOs including 302 Judges, and 804 1970 GTOs including 397 Judges) 1969 and 1970 model year F-body Ram Air IV cars were even rarer at just 245 total units produced. Only 157 Ram Air IV Firebirds, including 55 Trans Ams, were built for 1969. For 1970 the Trans Am was the only Firebird available with the Ram Air IV, and 88 were produced during the abbreviated 1970 F-body production run. A total of 1,808 Ram Air IV production cars were built over its 2-year production. Pontiac continued using its round-port cylinder-head design for 1971-'72 on the 455 HO. However, compression ratios were cut dramatically, marking the beginning of the end of the muscle car era. Ram Air V Though never factory-installed in any car, the ultimate engine of the Ram Air line of engines was the tunnel-port Ram Air V. In 1969 Pontiac created four versions of the Ram Air V engine: a short deck version for SCCA Trans-Am racing, a variant for NASCAR, a version for street use in GTOs and Firebirds, as well as a adaptation for drag racing. The cylinder head design is similar to the Ford FE tunnel-port head used in the GT40 and Can-Am series racing. So large are the intake ports that the pushrods