The third generation of the Pontiac Grand Prix, which had been new for 1969, received a pretty serious nose job for 1971. The quad headlamps were replaced by larger dual headlamps faired into the hood on either side of a jutting grille, giving the snout a sort of neoclassical appearance.
It was available in two levels of snarliness, the regular "J" model, which came with a 400, and the sportier "SJ", which had a 455 for a base motor. If the retro prow and SJ model designator made you think of the vanished Duesenberg, well, all the better. (Besides, they weren't around to protest, anyway.)
Personal luxury in the sporty grand touring mode was the name of the game, and plush bucket seats were separated by a console, while the instrument panel curved, cockpit-like, ahead of the driver.
The V-8 under the hood of the regular Grand Prix Model J was Pontiac's small-journal 400. For the 1971 model year, General Motors ordered all engines must take a compression haircut so as to run on regular gas, so the 6.6L Poncho motor now sported an 8.2:1 compression ratio. Horsepower was advertised in both gross and SAE net terms for '71, which meant 300 and 255, respectively. The standard transmission was a three-speed manual, with a four-speed and a Turbo Hydra-matic on the options list.
The hot-rodded example in the photo was snapped with a Canon EOS-1D Mark IV and an EF 24-105mm f/4L zoom lens in October of 2022.
Everyone has something that really doesn't matter at all that just ticks them off; for me it's people calling Pontiac V8's "large journal" and "small journal". Pontiac V8's were produced with FOUR main journal sizes. 1955 287 and 1956 317 had 2.5 inch main journals with a 3.25 inch stroke. 1957 347 and 1958 370 had 2.625 inch main journals to handle the longer 3.5625 inch stroke. These engines all had the standard for the time forged crankshafts and connecting rods. The 1959 389 had the stroke changed to 3.75 inches, and because GM made them introduce cast instead of forged crankshafts and connecting rods, the main journal size was enlarged to 3.00 inches. If they had today's computers and Finite Element Analysis (FEM) capabilities the Pontiac engineers would have known that this was overkill, but since slide rules were still the most advanced computer available to the engineers they went oversize to make sure nothing broke. Same for late 1961 when the 421 engine was introduced with a 4 inch stroke crankshaft and 3.25 inch main journals. Cadillac was the second GM division to start using cast cranks and rods when they re-designed their 390 in 1963, also changing their main journals from 2.625 to 3.00 inches to allow a stronger cast iron crankshaft with the same 3.88 inch stroke of the previous years forged crankshaft.
ReplyDeleteI get it, I really do!
DeleteI only do it because it's an intermediary step between the actual nerdy fact and the totally incorrect "big block/small block" nomenclature. You are absolutely correct, though.