JBA PERFORMANCE ENGINES - PONTIAC
Coming out of the 1950's Pontiac was dominant in stock car and drag racing, engineers and designers started the muscle car era, continuing the performance development program based off of one of General Motors best engine technology engineering teams. The Pontiac focus to maintain leadership was managed by key insiders including executives, engineers and marketers. These Pontiac enthsiasts stimulated an ongoing engine development programs designed to offer a wide variety of performance levels. These engine packages were integrated through various models thereby maintaining Pontiac's strong competitive tradition, while achieving innovative vehicle model leadership over a substantial period of time.
The 326, 350, 389 and 400 engine families introduction over an 8 year period culminated in full-size, mid-size cars and then pony car models. This popular power plant was able to dominate because common external engine dimensions included a cast iron block that packaged well into each chassis. The 326-400 engine family maintains a common crankshaft main journal of three inches with a variety of bore sizes ranging from 3.719" to 4.125" provided the increased cubic inches with great flexibility in performance and packaging. During this time the hottest 400 CID factory performance models were denoted by the Ram Air III and Ram Air IV designations and featured purpose built 4-bolt main blocks and high performance cylinder heads and induction systems. The exotic Ram Air V was a stand alone engine designed for a limited road racing series that required no larger than 305 CID. It featured the ultra-rare tunnel-port cylinder head design.
The big block 421, 428 and 455 Pontiac engine family, which dominated drag racing and stock car racing are physically and dimensionally able to also fit in popular mid-size Pontiac models. These big blocks used a 3.25 crankshaft main journal and physically also bolted in, helping the later Pontiac pony cars stoke up the performance well into the late 70's. These 421-455 engines are obvious when installed because of their unique configuration including a 4.094 - 4.150 big-block bore. The Super Duty and HO models were designed and cast with 4-bolt main blocks.
Pontiac Engine Families:
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