For the Pontiac fans
- Thread starter ZebraBlvd
- Start date
It's a great looking car although the jacked up rear end along with the deep offset rear wheels and tires sticking out of the fenders are going to turn away about 1/2 of the prospective buyers. The others will say things like "wow, cool ride, dude!"
A couple of things that look odd to me under the hood are the coil stuck way over on the left side with the hv wire pushed next to the ign module and the way the fuel filter is perched over the top of the therm housing. Picky details, I guess. Kinda hard to go on a test drive with no plates, too.
Still, a nice car, however.
Murray
A couple of things that look odd to me under the hood are the coil stuck way over on the left side with the hv wire pushed next to the ign module and the way the fuel filter is perched over the top of the therm housing. Picky details, I guess. Kinda hard to go on a test drive with no plates, too.
Still, a nice car, however.
Murray
thedelihaus
Nocturnal transmissions
I had a '68 Firebird. Nice cars.
Refresh my memory- besides the 455 and 428, what was Pontiac's other big block? The 400 was a smallblock.
Refresh my memory- besides the 455 and 428, what was Pontiac's other big block? The 400 was a smallblock.
thedelihaus
Nocturnal transmissions
rickon66, the 389 and 400 were actually off of Pontiac's proprietary small block, in regards to the actual "block", despite the larger size in displacement.
Thanks, rickon66, and Adam, about the other big block size.
I was 99.999% sure it was a 421, but couldn't recall for sure.
Thanks, rickon66, and Adam, about the other big block size.
I was 99.999% sure it was a 421, but couldn't recall for sure.
rickon66
Older Than Dirt
Here is a rundown of the variations of the SAME BASIC engine block produced by Pontiac from 1955 to 1981. From 287 cubic inches to 455 cu inches. The term small block and big block are used more in Chevy/Ford engines. The point I am trying to make is that all the Pointiac engines discussed are off the same basic block design.
[edit] 287
The V8 engine was introduced for the 1955 model year as the "Strato Streak". Not long before the model year introduction, Pontiac management decided that the entire line would be V8-powered. The 287 was an "oversquare" engine with a bore of 3.75 in (95.25 mm) and a stroke of 3.25 in (82.55 mm), for a total displacement of 287 in³ (4.7 L). Compression ratio was a modest 8.00:1, with valve diameters of 1.781 in (45.2 mm) (intake) and 1.500 in (38.1 mm). It was rated 180 hp (134 kW) @ 4600 rpm and 264 ft·lbf (358 N·m) @ 2400 rpm with a two-barrel carburetor, 200 hp (149 kW) @ 4600 rpm and 278 ft·lbf (377 N·m) @ 2800 rpm with the four-barrel carburetor.
[edit] 316
For 1956 the V8 was bored out to 3.9375 in (100.0 mm), increasing displacement to 316 in³ (5.2 L). It was offered in the following forms:
(with manual transmission)
two-barrel carburetor, 7.9:1 compression, 192 hp (143 kW) @ 4400 rpm, 297 ft·lbf (403 N·m) @ 2800 rpm
four-barrel carburetor, 8.9:1 compression, 216 hp (161 kW) @ 4800 rpm, 315 ft·lbf (427 N·m) @ 2800 rpm
(with Hydramatic)
two-barrel carburetor, 8.9:1 compression, 205 hp (153 kW) @ 4600 rpm, 294 ft·lbf (399 N·m) @ 2600 rpm
four-barrel carburetor, 8.9:1 compression, 227 hp (169 kW) @ 4800 rpm, 312 ft·lbf (423 N·m) @ 3000 rpm
two four-barrel carburetors, 10.5:1 compression, 285 hp (213 kW) @ 5100 rpm, 330 ft·lbf (447 N·m) @ 2600 rpm.
[edit] 336
The 336 in³ (5.5 L) engine was only used in GMC trucks. The stroke was 3.875 (98.4 mm) and the bore was 3.56 in. (90.4 mm).
[edit] 347
Pontiac V8 engine with Tripower carb setupFor 1957 the V8's stroke was increased to 3.56 in (90.4 mm), for a displacement of 347 in³ (5.7 L). For the first time, Pontiac offered Tri-Power, three two-barrel carburetors with a sequential linkage (replacing the previous dual-quad set-up). Power ratings increased accordingly:
(with manual transmission)
two-barrel carburetor, 8.5:1 compression, 227 hp (169 kW) @ 4600 rpm, 333 ft·lbf (451 N·m) @ 2300 rpm
four-barrel carburetor, 10:1 compression, 244 hp (182 kW) @ 4800 rpm, 350 ft·lbf (475 N·m) @ 2600 rpm
(with Hydramatic)
two-barrel carburetor, 10.0:1 compression, 244 hp (182 kW) @ 4800 rpm, 350 ft·lbf (475 N·m) @ 2600 rpm
four-barrel carburetor, 10.0:1 compression, 270 hp (201 kW) @ 4800 rpm, 359 ft·lbf (487 N·m) @ 2900 rpm
three two-barrel carburetors, 10.00:1 compression, 290 hp (216 kW) @ 5000 rpm, 375 ft·lbf (508 N·m) @ 2800 rpm.
Several dealer-installed camshafts were optional to increase power further to 310 hp (231 kW).
Standard only for the Pontiac Bonneville was Pontiac's first-ever fuel injection system. A mechanical system built by Rochester, it was similar in principle, but not identical, to the contemporary Chevrolet "fuelie". Pontiac did not release official power ratings for this engine, saying only that it had "more than 300 hp". Contemporary road tests suggest that it was actually somewhat inferior to the Tri-Power engines, although it did have better fuel economy. Only 630 Bonnevilles were produced for 1957, all of them fuel-injected.
[edit] 370
For 1958 the V8's bore was increased again to 4.06 in (103.2 mm), increasing displacement to 370 in³ (6.1 L).
The fuel-injected engine was now an option, not standard, on the Bonneville, carrying a staggering price tag of $500 (almost 15% of the car's base price). It was rated at 310 hp (231 kW) @ 4800 rpm and 400 ft·lbf (542 N·m) @ 3,000 rpm on 10.5:1 compression. Only about 400 were produced before the fuel injection system was quietly dropped.
[edit] 389
For 1959 the V8's stroke was increased to 3.75 in (95.3 mm), raising displacement to 389 in³ (6.4 L). The 389 would remain the standard Pontiac V8 engine through 1966, offered in a bewildering variety of outputs ranging from 215 hp to 360 hp (160 to 269 kW). The 389 was the standard engine for the Pontiac GTO through 1966.
[edit] 326
For 1963 Pontiac dropped the aluminum V8 it had offered on the Pontiac Tempest (which was built by Buick) and replaced it with a de-bored version of the standard Pontiac V8. It shared the 389's 3.75 in (95.3 mm) stroke, but its bore was reduced to 3.72 in (94.5 mm), giving it a displacement of 326 in³ (5.4 L). It was rated at 260 hp (193 kW) with a single, two-barrel carburetor. The 326 subsequently became the standard V8 engine for Tempests, and later the Pontiac Firebird, through 1967.
For 1967, its final year, a higher-output version, called the L76, had a four-barrel carb, dual exhausts, and higher compression, and was good for 285 hp (213 kW).
[edit] 400
For 1967, Pontiac introduced the 400 in³ (6.6 L). The 400 V8 was a bored-out 389 with 4.121 inch bore and 3.75 inch stroke (104.7 mm by 95.3 mm). It replaced the 389 and remained in production through the 1979 model year.
[edit] 421
The 421 in³ (6.9 L) was bored to 4.09 in (103.9 mm) and stroked to 4.00 in (101.6 mm), and also featured larger, 3.25 in (83 mm) main journals. Unlike previous enlargements of this engine, it did not replace the 389. Modified Super Duty versions of this engine were extensively used in NASCAR stock car racing and drag racing competition. The 421 also marked the end of the option for a forged steel crankshaft. The later produced 400, 350, and 455 engines, featured an Armasteel crankshaft, the standard crankshaft of the entire Pontiac V-8 line since introduction. "Armasteel" was no more than a fancy name for a hardened cast iron unit.
[edit] 428
In 1967 the 421 was bored to 4.12 in (104.7 mm), increasing its displacement to 428 in³ (7.0 L). It was replaced by the 455 for the 1970 model year.
[edit] 350
In 1968 the 326 was replaced by the 350, which used a 3.876 in bore and 3.75 in stroke (98.5 by 95.3 mm) for a total displacement of 350 in³ (5.7 L).
[edit] Ram Air V
(303, 366, 400, 455) In 1969 Pontiac created several versions of their "tunnel port" engine: a special short-deck version of the V8 for Trans Am racing and a 400 standard deck version. The factory also experimented with 366 and 455 in³ versions. The cylinder head was patterned after the highly successful Ford 427 tunnel port head. So large were the intake ports that the pushrods ran through the center of the ports via pressed-in tubes.
303 - The revised engine had shorter connecting rods, smaller 2.5 in. (63.5 mm) journals, special "tunnel port" heads, and a solid-lifter version of the 400's Ram Air IV camshaft. It shared the 4.125 in (104.8 mm) bore of the 400, but with a 2.84 in (72.1 mm) stroke for a displacement of 303 in³ (5.0 L). The short-deck engine weighed about 40 lb (18 kg) less than the 400, and had an 8000 rpm redline. The 303 program was promising, with race-ready engines producing 475-525 hp (354.4-391.7 kW) and slated for advertised ratings of 355 hp in the Pontiac Firebird and 375 hp for the Pontiac GTO. Concerns about emissions, the response of the automobile safety lobby, and the warranty implications of a high-revving street engine led to its cancellation. SCCA Trans-Am series General Competition Rules required an engine to be a "Production" item, and required a production of no less than 250 units. The total number of Ram Air V 303 engines produced is not known, estimates range from the SCCA required 250 units, up to 500 units, with rumors of a handfull of Ram Air V 303's making their way into the Pontiac Trans-Am production line. These engines are extremely rare and parts not readily available.
[edit] 455
For 1970, the 428 bore was expanded to 4.152 inches, combined with a 4.21 inch stroke (105.5 mm by 106.9 mm), yielding a total displacement of 455 in³ (7.5 L). The engine became available for the first time in Pontiac Firebirds and the Pontiac GTO, as GM lifted its restrictions on the use of big-block engines in mid-sized cars. The Pontiac V8 design differs from other manufacturer's designs in that the external dimensions of each engine, from 326 - 455 in³ displacement, is identical. The displacement is determined internally with changes to the bore and stroke; therefore, there is no "big block" Pontiac engine. The 455 was used through 1976.
The 455, with its "undersquare" dimensions (long stroke relative to bore), emphasized torque over hp, and was somewhat less powerful than some high-performance iterations of the 400. For 1971 Pontiac introduced a High Output, H.O., version with stronger internal parts and improved cylinder head design for better breathing, making some 335 hp/224 kW (310 hp in the more accurate SAE net system), but this was an extremely rare engine. In 1973, a further refined and even stronger version, the Super Duty (SD) engine was introduced with "only" 310 hp/231 kW (SAE net) using a similar camshaft specifications to the Ram Air IV 400 and similar round port cylinder heads with specific "LS2" intake and cast iron exhaust header-manifolds. Still, it was the strongest American engine offered that year. Its power was achieved through bending of EPA emissions-testing procedures, which led engineers to de-tune the engine to 290 hp (216 kW) via a camshaft change for mid 1973 and 1974, after which point it was discontinued.
While an evolution of the RAIV and H.O. engine designs, the 455 SD was a much improved engine. In addition to thicker casting of the block, refined cylinder heads, reinforcements in the lifter galley and improvements to the crankshaft and connecting rods, the SD was made with a provision for dry sump oiling from the factory. This truly was a racing engine, detuned for use in passenger cars
[edit] 287
The V8 engine was introduced for the 1955 model year as the "Strato Streak". Not long before the model year introduction, Pontiac management decided that the entire line would be V8-powered. The 287 was an "oversquare" engine with a bore of 3.75 in (95.25 mm) and a stroke of 3.25 in (82.55 mm), for a total displacement of 287 in³ (4.7 L). Compression ratio was a modest 8.00:1, with valve diameters of 1.781 in (45.2 mm) (intake) and 1.500 in (38.1 mm). It was rated 180 hp (134 kW) @ 4600 rpm and 264 ft·lbf (358 N·m) @ 2400 rpm with a two-barrel carburetor, 200 hp (149 kW) @ 4600 rpm and 278 ft·lbf (377 N·m) @ 2800 rpm with the four-barrel carburetor.
[edit] 316
For 1956 the V8 was bored out to 3.9375 in (100.0 mm), increasing displacement to 316 in³ (5.2 L). It was offered in the following forms:
(with manual transmission)
two-barrel carburetor, 7.9:1 compression, 192 hp (143 kW) @ 4400 rpm, 297 ft·lbf (403 N·m) @ 2800 rpm
four-barrel carburetor, 8.9:1 compression, 216 hp (161 kW) @ 4800 rpm, 315 ft·lbf (427 N·m) @ 2800 rpm
(with Hydramatic)
two-barrel carburetor, 8.9:1 compression, 205 hp (153 kW) @ 4600 rpm, 294 ft·lbf (399 N·m) @ 2600 rpm
four-barrel carburetor, 8.9:1 compression, 227 hp (169 kW) @ 4800 rpm, 312 ft·lbf (423 N·m) @ 3000 rpm
two four-barrel carburetors, 10.5:1 compression, 285 hp (213 kW) @ 5100 rpm, 330 ft·lbf (447 N·m) @ 2600 rpm.
[edit] 336
The 336 in³ (5.5 L) engine was only used in GMC trucks. The stroke was 3.875 (98.4 mm) and the bore was 3.56 in. (90.4 mm).
[edit] 347
Pontiac V8 engine with Tripower carb setupFor 1957 the V8's stroke was increased to 3.56 in (90.4 mm), for a displacement of 347 in³ (5.7 L). For the first time, Pontiac offered Tri-Power, three two-barrel carburetors with a sequential linkage (replacing the previous dual-quad set-up). Power ratings increased accordingly:
(with manual transmission)
two-barrel carburetor, 8.5:1 compression, 227 hp (169 kW) @ 4600 rpm, 333 ft·lbf (451 N·m) @ 2300 rpm
four-barrel carburetor, 10:1 compression, 244 hp (182 kW) @ 4800 rpm, 350 ft·lbf (475 N·m) @ 2600 rpm
(with Hydramatic)
two-barrel carburetor, 10.0:1 compression, 244 hp (182 kW) @ 4800 rpm, 350 ft·lbf (475 N·m) @ 2600 rpm
four-barrel carburetor, 10.0:1 compression, 270 hp (201 kW) @ 4800 rpm, 359 ft·lbf (487 N·m) @ 2900 rpm
three two-barrel carburetors, 10.00:1 compression, 290 hp (216 kW) @ 5000 rpm, 375 ft·lbf (508 N·m) @ 2800 rpm.
Several dealer-installed camshafts were optional to increase power further to 310 hp (231 kW).
Standard only for the Pontiac Bonneville was Pontiac's first-ever fuel injection system. A mechanical system built by Rochester, it was similar in principle, but not identical, to the contemporary Chevrolet "fuelie". Pontiac did not release official power ratings for this engine, saying only that it had "more than 300 hp". Contemporary road tests suggest that it was actually somewhat inferior to the Tri-Power engines, although it did have better fuel economy. Only 630 Bonnevilles were produced for 1957, all of them fuel-injected.
[edit] 370
For 1958 the V8's bore was increased again to 4.06 in (103.2 mm), increasing displacement to 370 in³ (6.1 L).
The fuel-injected engine was now an option, not standard, on the Bonneville, carrying a staggering price tag of $500 (almost 15% of the car's base price). It was rated at 310 hp (231 kW) @ 4800 rpm and 400 ft·lbf (542 N·m) @ 3,000 rpm on 10.5:1 compression. Only about 400 were produced before the fuel injection system was quietly dropped.
[edit] 389
For 1959 the V8's stroke was increased to 3.75 in (95.3 mm), raising displacement to 389 in³ (6.4 L). The 389 would remain the standard Pontiac V8 engine through 1966, offered in a bewildering variety of outputs ranging from 215 hp to 360 hp (160 to 269 kW). The 389 was the standard engine for the Pontiac GTO through 1966.
[edit] 326
For 1963 Pontiac dropped the aluminum V8 it had offered on the Pontiac Tempest (which was built by Buick) and replaced it with a de-bored version of the standard Pontiac V8. It shared the 389's 3.75 in (95.3 mm) stroke, but its bore was reduced to 3.72 in (94.5 mm), giving it a displacement of 326 in³ (5.4 L). It was rated at 260 hp (193 kW) with a single, two-barrel carburetor. The 326 subsequently became the standard V8 engine for Tempests, and later the Pontiac Firebird, through 1967.
For 1967, its final year, a higher-output version, called the L76, had a four-barrel carb, dual exhausts, and higher compression, and was good for 285 hp (213 kW).
[edit] 400
For 1967, Pontiac introduced the 400 in³ (6.6 L). The 400 V8 was a bored-out 389 with 4.121 inch bore and 3.75 inch stroke (104.7 mm by 95.3 mm). It replaced the 389 and remained in production through the 1979 model year.
[edit] 421
The 421 in³ (6.9 L) was bored to 4.09 in (103.9 mm) and stroked to 4.00 in (101.6 mm), and also featured larger, 3.25 in (83 mm) main journals. Unlike previous enlargements of this engine, it did not replace the 389. Modified Super Duty versions of this engine were extensively used in NASCAR stock car racing and drag racing competition. The 421 also marked the end of the option for a forged steel crankshaft. The later produced 400, 350, and 455 engines, featured an Armasteel crankshaft, the standard crankshaft of the entire Pontiac V-8 line since introduction. "Armasteel" was no more than a fancy name for a hardened cast iron unit.
[edit] 428
In 1967 the 421 was bored to 4.12 in (104.7 mm), increasing its displacement to 428 in³ (7.0 L). It was replaced by the 455 for the 1970 model year.
[edit] 350
In 1968 the 326 was replaced by the 350, which used a 3.876 in bore and 3.75 in stroke (98.5 by 95.3 mm) for a total displacement of 350 in³ (5.7 L).
[edit] Ram Air V
(303, 366, 400, 455) In 1969 Pontiac created several versions of their "tunnel port" engine: a special short-deck version of the V8 for Trans Am racing and a 400 standard deck version. The factory also experimented with 366 and 455 in³ versions. The cylinder head was patterned after the highly successful Ford 427 tunnel port head. So large were the intake ports that the pushrods ran through the center of the ports via pressed-in tubes.
303 - The revised engine had shorter connecting rods, smaller 2.5 in. (63.5 mm) journals, special "tunnel port" heads, and a solid-lifter version of the 400's Ram Air IV camshaft. It shared the 4.125 in (104.8 mm) bore of the 400, but with a 2.84 in (72.1 mm) stroke for a displacement of 303 in³ (5.0 L). The short-deck engine weighed about 40 lb (18 kg) less than the 400, and had an 8000 rpm redline. The 303 program was promising, with race-ready engines producing 475-525 hp (354.4-391.7 kW) and slated for advertised ratings of 355 hp in the Pontiac Firebird and 375 hp for the Pontiac GTO. Concerns about emissions, the response of the automobile safety lobby, and the warranty implications of a high-revving street engine led to its cancellation. SCCA Trans-Am series General Competition Rules required an engine to be a "Production" item, and required a production of no less than 250 units. The total number of Ram Air V 303 engines produced is not known, estimates range from the SCCA required 250 units, up to 500 units, with rumors of a handfull of Ram Air V 303's making their way into the Pontiac Trans-Am production line. These engines are extremely rare and parts not readily available.
[edit] 455
For 1970, the 428 bore was expanded to 4.152 inches, combined with a 4.21 inch stroke (105.5 mm by 106.9 mm), yielding a total displacement of 455 in³ (7.5 L). The engine became available for the first time in Pontiac Firebirds and the Pontiac GTO, as GM lifted its restrictions on the use of big-block engines in mid-sized cars. The Pontiac V8 design differs from other manufacturer's designs in that the external dimensions of each engine, from 326 - 455 in³ displacement, is identical. The displacement is determined internally with changes to the bore and stroke; therefore, there is no "big block" Pontiac engine. The 455 was used through 1976.
The 455, with its "undersquare" dimensions (long stroke relative to bore), emphasized torque over hp, and was somewhat less powerful than some high-performance iterations of the 400. For 1971 Pontiac introduced a High Output, H.O., version with stronger internal parts and improved cylinder head design for better breathing, making some 335 hp/224 kW (310 hp in the more accurate SAE net system), but this was an extremely rare engine. In 1973, a further refined and even stronger version, the Super Duty (SD) engine was introduced with "only" 310 hp/231 kW (SAE net) using a similar camshaft specifications to the Ram Air IV 400 and similar round port cylinder heads with specific "LS2" intake and cast iron exhaust header-manifolds. Still, it was the strongest American engine offered that year. Its power was achieved through bending of EPA emissions-testing procedures, which led engineers to de-tune the engine to 290 hp (216 kW) via a camshaft change for mid 1973 and 1974, after which point it was discontinued.
While an evolution of the RAIV and H.O. engine designs, the 455 SD was a much improved engine. In addition to thicker casting of the block, refined cylinder heads, reinforcements in the lifter galley and improvements to the crankshaft and connecting rods, the SD was made with a provision for dry sump oiling from the factory. This truly was a racing engine, detuned for use in passenger cars
thedelihaus
Nocturnal transmissions
Well scratch my ass and call me uncle...
thanks for the detailed info. Very, very appreciated.
I started reading Car Craft, Hot Rod, and Pontiac Magazine back in the mid 80s, after spying a cream colored 1968 Firebird up the street. I've picked up some misinformation along the way it sounds like. Or I just misread, or misunderstood something along the way.
I thought that anything past the 400 was a different block, heads from the 326 to the350 to the 389 to the 400 were swappable, but not the 421, 428 and 455 (the trio interchangeable with each other though), due to differences in the block casting. Also thought the motor mounts were different after the 400, due to block differences- me thinking size (width) and casting.
So, it seems above the 400 ci model, starting with the 421, the crank journals are larger? Is that correct? Maybe that's where I was getting a "small block" "big block" difference.
It sounds like any bore can be done on all the blocks too, since the blocks are really the same cast. Yes? Any head will bolt on, even if they may not work well due to bore/stroke factors?
thanks for the detailed info. Very, very appreciated.
I started reading Car Craft, Hot Rod, and Pontiac Magazine back in the mid 80s, after spying a cream colored 1968 Firebird up the street. I've picked up some misinformation along the way it sounds like. Or I just misread, or misunderstood something along the way.
I thought that anything past the 400 was a different block, heads from the 326 to the350 to the 389 to the 400 were swappable, but not the 421, 428 and 455 (the trio interchangeable with each other though), due to differences in the block casting. Also thought the motor mounts were different after the 400, due to block differences- me thinking size (width) and casting.
So, it seems above the 400 ci model, starting with the 421, the crank journals are larger? Is that correct? Maybe that's where I was getting a "small block" "big block" difference.
It sounds like any bore can be done on all the blocks too, since the blocks are really the same cast. Yes? Any head will bolt on, even if they may not work well due to bore/stroke factors?
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