Pontiac Engine History

by **69_RAG_TOP** Sat Apr 07, 2012 1:06 am

How many engines did Pontiac Division of General Motors design over its lifetime?

Most people can name the 301, 350, 400, 455 ... so would you say Four, Five, Six, Seven... More?

Remember that the 305 is a Chevy motor so we can exclude that one.

Let's not forget John DeLorean's Pontiac OHC six cylinder 250. And we can skip the four cylinder 195 cu in which was the most unusual variation of the durable Pontiac V8 was not a V8 at all, but an inline four. Nicknamed the "INDY 4", created for the 1961 Pontiac Tempest Pontiac; it was essentially the right bank of the 389.

So....would you believe over 20 different engines? Let's start.

287

The V8 engine was introduced for the 1955 model year as the "Strato Streak". Pontiac management decided that the entire line would be V8-powered. This was based on results of over 1 million test miles, which was unheard of at the time.

316

For 1956 the V8 was bored out to 3 ¹⁵⁄₁₆ in, increasing displacement to 316.6 cu in.

347

For 1957 the V8's stroke was increased to 3 ⁹⁄₁₆ in for a displacement of 347 cu). For the first time, Pontiac offered Tri-Power, three two-barrel carburetors with a sequential linkage.

370

For 1958 the V8's bore was increased again to 4 ¹⁄₁₆ in, increasing displacement to 369.4 cu in. The engine is now called the TEMPEST V-8 and will be called this until the end of 1960.

389

For 1959 the V8's stroke was increased to 3.75 in, raising displacement to 388.9 cu in. The 389 would remain the standard Pontiac V8 engine through 1966, offered in a bewildering variety of outputs ranging from 215 to 368 horsepower.

326

Pontiac 326 engine in 1967 Firebird

In 1964 when the new "A" body intermediates came out there was a new corporate (GM) engine size limitation to anything less than 330 cu. in. and so the 326 bore size was reduced to 3.72 giving a true 326 cu.in. The 326 subsequently became the optional V8 engine for Tempests, and later the Pontiac Firebird through 1967.

400

For 1967, Pontiac introduced the 400 cu in.

The '400' V8 was essentially a bored-out (+.060) 389 with 4.1225-inch bore and 3.75-inch stroke.. It replaced the 389 in 1967 and remained in production through the 1978 model year. The 1979 cars with a 400, had an engine produced in 1978.

350

In 1968 the 326 was replaced by the 350, which used a 3.8750 in bore and 3 ³⁄₄ in stroke for a total displacement of 354.71 cu in, although it was still called a 350. This engine was offered in both 2bbl and 4-barrel variations similar to the previous 326 engine. In 1968 an HO option was available in the Tempest and Firebirds that was rated at 320 hp.

303

In 1969, Pontiac unveiled its Trans Am model Firebird, and since racing rules required a sub-305 cid engine, Pontiac unveiled the 303 for racing models only, never available to the public. Bore and stroke were 4 ¹⁄₈ x 2 ¹³⁄₁₆, for 300.7 cu in. It was rated at 475 hp.

301

The 301.6 cu in was offered from 1977 to 1981 and also installed in other GM cars during those years. The 301 had a 4.00 in bore and 3.00 in stroke. Based in part on designs for the "short deck" 303 cu in engine designed for the 1970 racing season, it had a shorter deck than the big V8, and used thin-wall castings to reduce weight.

265

Based on the same short-deck as the 301, the 265.1 cu in was offered only in 1980 and 1981, and featured a smaller bore of 3.75 in coupled with the same 3.00 in stroke of the 301. It produced 135 hp.

421

Introduced in 1961 as a dealer installed Super Duty option that had dual four barrels, the 421 cu in was bored to 4 ³⁄₃₂ in and stroked to 4.00 in. The 421 SD became factory installed in 1962 and in 1963 a street version became available from the factory with a four-barrel or tri-power carburetion.

428

In 1967 the 421 was bored to 4 ¹⁄₈ in , increasing its displacement to 427.6 cu in. The 428 had the same 4.00" stroke as the 421, and was produced from 1967 to 1969. This engine produced 370 hp, or 390 hp in High Output (H.O.) form.

455

For 1970 through 1976, the 428 bore was expanded .030" to 4.155 inches , combined with a 4 ⁷⁄₃₂ stroke, yielding a total displacement of 457.6 cu in.

The Super Dutys

SD389

SD421

SD455

Available only in the 1973 and 1974 Formula Firebird and Firebird Trans AM, the SD-455 consisted of a strengthened cylinder block that included 4 bolt main bearings and additional material in various locations for improved strength.

Whew! And we have not even gotten to the RAM engines yet!

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by Formulabruce Sun Apr 15, 2012 12:01 pm

1. mentioned, but there was two
The 230 Cu in OHC 6
The 250 cu in OHC 6
The 250 cu in OHC 6 4 Bbl
2. 1972 SD 455, not yet available, but there is ONE Factory 72 SD455!
Pontiac Engine History 72ta20.1

What about the Pontiac 215?

Pontiac Engine History

Pontiac Engine History

Re: Pontiac Engine History