query: Is the small-block engine a combustion engine?
passage: Chevrolet small-block engine
After the 1967 Trans-Am campaign with the 4-Bbl induction system producing more horsepower than the competing auto makers' 8-Bbl systems, for 1968 Chevrolet developed a factory 'cross-ram' aluminum intake-manifold package using two Holley 600cuft/min (17m3/min) mechanical secondary carburetors for Trans-Am racing. It was available only as off-road service parts purchased over the Chevrolet dealership parts counter. With the Chevrolet '140 1st-design off-road cam, the package increased a stock 302's horsepower from 360hp (268kW) to approximately 400hp (298kW). Chevrolet went so far as to carry the positive crankcase ventilation system (PCV) over to the cross-ram induction system to retain emissions compliance mandated for US-produced cars beginning in 1967, that also provided full-throttle crankcase pressure venting to the intake air to burn its vapors. Engines prepared for competition use were capable of producing 465hp (347kW) with little more than the 8-Bbl induction, ported heads with higher pressure valvesprings, roller rocker arms, and the '754 2nd-design road-race cam. 1967/1968 models' cowl-induction system had an enclosed air-cleaner assembly ducted from its passenger side into the firewall cowl above the heater core. In 1969, factory Z/28's could be ordered with the ZL-1 aluminum-block 427 adaption of the 1967 L-88 427 Corvette cowl-induction 'ZL-2' hood available for both single and dual four-barrel induction systems that were sealed to the air cleaner base ensuring dense cooler, high-pressure, oxygen-laiden air from the center of the base of the windshield was supplied to the engine for combustion smoothness and maximum power production. Another popular service-parts-only component used on the 302 was the magnetic-pulse Delco transistor-ignition ball bearing distributor. Introduced in 1963 on Pontiac's 389 and 421cuin (6.4 and 6.9L) drag racing engines, General Motors fitted it to the 1967 Z/28 before they used it on the L88 427cuin (7.0L) Corvette. It eliminated the production breaker-point ignition allowing greater spark energy and more stable ignition timing at all engine speeds including idle. This was one of the least talked about yet most transformative and comprehensive performance and durability upgrades of its time. Many of the 302s off-road service parts were the development work of racers like Roger Penske. Every part in a SCCA Trans-Am engine had to be available through local Chevrolet parts departments to encourage their use by anyone who wanted them.
passage: LS based GM small-block engine
LS7.R