with no space for coolant to flow between the cylinders. Additionally, the 403 had windowed main webs, which reduced the internal strength of the block in the crankcase area. It has been purported that there is a 403 Oldsmobile block and cast that has solid main webs that may have been equipped in vehicles such as the Pontiac Firebird equipped with a towing package, but there are currently no clearly documented surviving examples. The 403 is fundamentally the exact same block as an Oldsmobile 350 V8, however it features a larger bore. Most components and accessories are interchangeable. A popular modification made to the 403 to increase power was to swap on early Oldsmobile 350 heads to boost compression. The 403 was never featured with a manual transmission and the crank was never manufactured for a pilot bearing. It was generally paired with the Turbo Hydramatic 350 3-speed automatic or the Turbo Hydramatic 400 3-speed ustomatic in rear wheel drive vehicles, in the case of front-wheel drive vehicles, the Turbo Hydramatic 425 FWD 3-speed automatic. It always featured the 4A 83cc heads with 8:1 compression, and a Rochester Quadrajet 4 barrel carburettor. The 403 Oldsmobile was generally painted "Corporate GM Blue" on every model line it was equipped in. The Olds 403 was used by Buick and Pontiac in addition to Oldsmobile until its discontinuation after 1979. Output was and . Uniquely in the 1977 Toronado, the 403 engine was fitted with a crank triggered ignition system. Parts peculiar to this system include a toothed disc between the harmonic balancer and the crank pulley, the "adjacent sensor" (an early form of crankshaft position sensor), a special distributor, an engine temperature sensor, and a rudimentary computer mounted inside the car, under the dashboard. Applications: 1977 Buick Century Estate 1977–1978 Buick Riviera 1977–1979 Buick Electra 1977–1979 Buick Estate Wagon 1977–1979 Buick LeSabre 1977 Oldsmobile Cutlass 1977 Oldsmobile 4-4-2 1977 Oldsmobile Vista Cruiser 1977–1978 Oldsmobile Delta 88 1977–1978 Oldsmobile Toronado 1977–1979 Oldsmobile 98 1977–1979 Oldsmobile Custom Cruiser 1977 Pontiac Bonneville 1977-1979 Pontiac Catalina Safari 1977-1979 Pontiac Firebird 1977 Pontiac Grand Prix available with California Emissions Only 1977 Pontiac Can Am available with California Emissions Only 1977–1978 GMC Motorhome 260 A smaller V8 was created for the new Oldsmobile Omega in 1975 by decreasing the bore to . It produced net and . SAE gross power was 150 hp. The 260 V8 received VIN