When compared to the 72-cc casting, airflow is negatively affected. This particular 1961 Ventura, campaigned by Royal Pontiac and driven by Wangers, may be the only 1961 Pontiac to receive a factory-installed Super Duty 389. Emissions and Economy New federal emission standards shook the industry during the 1975 model year. The closer the valves are to the cylinder walls, the more shrouding that occurs, which can negatively impact airflow. A fuel octane rating of 91 is the highest commonly available at gas station pumps today. To combat certain forms of tailpipe emissions and to keep insurance premiums in check, General Motors imposed a corporate compression ratio limit of 8.
Fewer than 1,300 were built during its two-year run. I commonly use the compression calculator on the Performance Trends Engine Analyzer program to calculate the static and dynamic ratios of various engines. The Ram Air package became a Pontiac trademark for years to follow. Now, there are probably as many engine parameters as there are engineers to think them up. Engines featuring a compression ratio of 7. When you consider that most modern builds include at least a 460-ci engine, the cast port volume is adequate for strong peak horsepower, and nearly ideal for the larger 500-plus-inch engines that are so common today.
As a matter of fact, for superior flame propagation best horsepower , it is best to use a flat top piston. When General Motors pulled the plug on factory-backed racing, Pontiac moved forward with its street performance program. You can make almost 500ci from a 400, 428 or 455 block with the 4. Its robust design allowed immediate adaptability to future displacement increases. Ignition timing is different, you want it all in by 2500rpm.
It is truly a Pontiac trademark. That improves idle quality and low-speed street manners, particularly in applications where a radical camshaft dilutes the incoming mixture with residual exhaust gas. If your build deviates from these, I strongly suggest you consult with your builder to determine the effects that might have. It can, however, have adverse side effects on the street. Starting at 287 ci for 1955, displacement increased in each of the succeeding years, while basic architecture of the V8 went unchanged.
You must then multiply the result by the number of cylinders for the subject engine, 8 in the instance of the Pontiac. Any other engines in the 400-455 family? So far, it seems that the 350 has a smaller bore, but the 400 and 455 share the same bores, but different strokes. With more compression, dual 4-barrel carburetors, and a special camshaft, the combination boosted horsepower to 285. Guys like Hand have done the hard research before all the neat new shiny stuff was available and passed it on to everyone, some of whom now regurgitate it as though they discovered it themselves. The as-cast intake port volume measures 310 cc, and it peaks at 414 cfm of intake airflow. A vacuum advance canister senses engine load and adds timing in certain operating conditions to improve engine efficiency.
Electronic Ignition System Since the 1960s, Pontiac has used various ignition systems that were electronically triggered. With the significant cost of 91- to 93-octane fuel these days, combinations compatible with 89-octane gas are gaining popularity. The Ram Air V was a tunnel-port engine that Pontiac developed during the late 1960s. SuperFlow Corporation is an airfl ow industry leader and it has developed a mathematical equation that can predict approximate horsepower based upon airflow at a specific test pressure. Beginning in 1968, Pontiac located the block casting number on a ledge just rearward of the No.
Many professional Pontiac engine builders can supply a pair of cylinder heads that are tailored for your specific engine. The oversized block was created by taking the heavy-duty 389 and increasing the bore diameter to 4. Most every other cast-aluminum Pontiac cylinder head available on the aftermarket today features a fast-burn combustion chamber. This book will have new information for everyone and will be a must-have for longtime enthusiasts and new owners alike! The front oil-galley plugs in most stock Pontiac blocks are a press-fit design that are driven into place and staked for maximum retention. Stock lifter bores supply a relatively large volume of oil for proper hydraulic lifter operation. The 350 can spin, and so can a 455 with light slugs and good rods, but there isnt much need to until the heads flow more than 330cfm. So the 400 and 350 use the same crank with difference balance.
That then grew to 455 ci for 1970 when a new crankshaft with a 4. Several thousand were set aside for the 1979 Trans Am. For a race engine do the same thing as a street engine, but crank the compression and airflow, then make the car really light. Some builds include a stock Pontiac block while others use an aftermarket block, some are naturally aspirated while others use forced induction or accommodate nitrous oxide, and some operate on commonly available pump gas while others require race gas. A static ratio uses the physical measurements of a particular engine to mathematically calculate an actual ratio. The larger 87-cc chamber relocates the valve seat and positions it higher in relation to the port floor. We review a lot of engine tech books and find this iteration of CarTech's max power Pontiac book an informative look at what's currently out there in the world of high-performance Pontiac hardware.