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headers bolt to the heads,lol.
tube size and length is related to horse power produced with the sum of all parts.

dont buy big tube race headers for a mild street engine. 2 inch primaries are good to 650 hp or more.
Tell us about your application?
 

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Lots of variables, around town just crooozin you probably wouldn't notice anything except maybe the sound. Headers, and I mean GOOD long tube headers really make a difference performance wise at higher RPM. In a dyno application I've read where headers make as much as 30 or more HP......but again that's at higher rpm.
 

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Discussion Starter · #4 ·
headers bolt to the heads,lol.
tube size and length is related to horse power produced with the sum of all parts.

dont buy big tube race headers for a mild street engine. 2 inch primaries are good to 650 hp or more.
Tell us about your application?
So its a 1974 chevy shortbox 4x4 I had a 402 in it prety much stock til we pulled it the other day and found 1 broken piston and 1 or 2 pistons w/ broken rings...we were gona rebild it til today my dad herd of a 70's pickup with a 454 so i mite go take a look at that soon and maybe put it in my '74...if that 454 just has regular exhaust manifolds should i use them or my headers??
 

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Take the time to use wire looms and separators to keep the wires neat and tidy and away from headers. If the wires get close to a header pipe the put heat socks over the ends of the wires.
 

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In 1970, GM pushed the performance bar higher with the introduction of the Chevy 454 V8. Unlike the popular Chevy 427 that was used in a wide variety of automobiles, the 454 was used only in high performance cars like the Chevy Camaro, Corvette and Chevelle. There were 3 different variations of the 454 that came onto the drawing board at GM during the 70s; the LS5, the LS6, and the LS7 which was designed but not produced for the general public most likely due to the massive smog restrictions that started lurking about in the early 70s. . Although the LS7 454 never made its way into any cars sold to the public, it was sold as a crate engine available through Chevrolet and claimed to produce around 500 horsepower.
 

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TAKE A KID TO A CAR SHOW
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Its a breath of fresh air to see a young man on here that actually puts his age down :thumbup: And is willing to learn!!!!!! I'd like to shake your hand young man:thumbup: But a hardy welcome :welcome: Is owed you!!


Jester:D
 

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If the truck and engine are both 1968 it is probably a 396 ci or 427 ci. Both are good engines. Hereis alist of big block casting numbers. Print it.
Casting Number
Years
CID
340220
72-76
427
Truck Tall deck
345014
74-86
454
Truck
346236
74-76
454
2-bolt
359070
74-90
454
Truck
361959
73-85
454
Car & Truck
364776
68-84
427
Truck Tall deck
364779
68-88
366
Truck Tall deck
399204
70-71
509
4-Bolt Aluminum Can-AM
399289
73-79
454
2-bolt
399293
77-78
366
Truck
473478
68-84
427
Truck Tall deck
3716362
396
3732755
59-61
348
3732811
58
348
3751872
58
348
3755011
59-61
348
3771705
59-61
348
3782012
58-61
348
3782870
68-76
427
Truck Tall deck
3788068
62
409
3795623
61
409
3798962
62-65
348
Truck
3815707
58-61
348
3824553
66-67
366
Truck
3830814
63
409
3839752
62-63
409
3839754
65
409
3844422
64
409
3855961
66-67
396
2-bolt
3855962
65-66
396
4-Bolt
3855977
65-67
366
Truck Tall deck
3857651
409
Marine
3857655
62-65
348
Truck
3857656
65
409
3857658
409
Marine
3860386
62-64
409
3860387
58
348
3869942
66-67
427
2 & 4-Bolt
3873858
66
396
4-Bolt
3902406
67
396
2 & 4-Bolt
3902466
65-67
396
3904351
67
427
2 & 4-Bolt
3904354
66-67
366
Truck Tall deck
3916319
68-85
366
Truck Tall deck
3916321
68
427
2 & 4-Bolt
3916323
68
396
2 & 4-Bolt
3918319
66-70
366
Truck
3925521
68-85
366
Truck Tall deck
3935439
68-69
427
2 & 4-Bolt
3935440
68-69
396
2 & 4-Bolt
3937724
68-85
366
Truck Tall deck
3937726
68-84
427
Truck Tall deck
3946052
69
427
ZL-I Aluminum 4-Bolt
3946053
97
427
ZL-I Aluminum 4-Bolt 2nd design
3955270
69
427
2 & 4-Bolt
3955272
69
396/402
2 & 4-Bolt
3955274
68-85
366
Truck Tall deck
3955276
68-84
427
Truck Tall deck
3963512
69-71
427/454
2 & 4-Bolt COPO
3963513
73-76
454
3965440
68-69
396
3965449
68-72
396
3969852
68-84
366
Truck
3969854
69-72
396/402/454
2 & 4-Bolt
3969858
68-84
427
Truck Tall deck
3995623
61
409
3999289
72-78
454
Car & Truck 2-Bolt
3999290
72
402
2-bolt
3999293
68-85
366
Truck Tall deck
3999294
68-84
427
Truck Tall deck
6272176
68-76
366
Truck
6272177
72
402
2-bolt
6272181
73-76
427
Truck
10051107
454
4-Bolt Bowtie IV Short deck
10068286
90-91
454
4-Bolt IV Short deck
10069284
427
Truck
10114182
91-95
454
4-Bolt Gen-5
10114183
91-95
366
Truck Gen-5
10114184
91-95
427
Truck Gen-5
10134366
454
4-Bolt Gen-5 Bowtie Tall deck
10185050
454
4-Bolt Gen-5 Bowtie Short deck
10237297
96-up
454
4-Bolt Vortec 7400 Gen-6
10237300
96-up
502
4-Bolt 4.466 bore Gen-6
12550313
91-95
454
4-Bolt Gen-5
12556110
01-up
496
4-Bolt Vortec 8100 Gen-7
14015445
75-90
454
Car & Truck
14015543
87-90
454
4-Bolt Gen-5
14044807
454
4-Bolt IV Bowtie Tall deck
14096859
502
4-Bolt Gen-5
24502504
454
4-Bolt Gen-5 Bowtie Short deck
24502572
4-Bolt DRCE-2 Olds "9.5"" deck"
 

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If the truck and engine are both 1968 it is probably a 396 ci or 427 ci. Both are good engines.

So did they Ever put a 454 in a pickup from the factory??
This may help!:thumbup:
the 396 was actually only put in 68 and 69 trucks, after 1969 they didn't make any more 396 big blocks, they were all 402.


Jester:D



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The 396-cubic-inch (6.5 L) V8 was introduced in the 1965 Corvette as the L78 option and in the Z16 Chevelle. It had a bore of 4.094 in (104.0 mm) and a stroke of 3.76 in (96 mm), and produced 375 hp (280 kW) and 415 lb·ft (563 N·m). This version of the 396 was equipped with four bolt main bearing caps and was very comfortable with being operated in the upper 6000 rpm range.

Introduced in 1970, the 402-cubic-inch (6.6 L) was a 396-cubic-inch bored out by 0.030 in (0.76 mm). Despite the fact that it was 6 cubic inches (98 cc) larger, Chevy continued marketing it under the popular "396" label in the smaller cars while at the same time labeling it "Turbo-Jet 400" in the full-size cars. The 402 label was used in Light Pickup Trucks.

The 366 Big block V-8 (6.0 L) gasoline engine was used only in Chevrolet Medium duty trucks and in school buses. It had a bore of 3.935" and a stroke of 3.760". This engine was made from the 1960s until the mid-1990s. The 366 used 4 compression rings on the pistons as it was designed from the very beginning as a truck engine. The 366 was only produced as a tall deck engine with a 0.400" taller deck than the 396, 402, & 454 short deck big blocks.


Mark IV engines saw extensive application in Chevrolet and GMC medium duty trucks, as well as in Blue Bird Corporation All American and TC/2000 transit buses (the latter up until 1995, using a purpose-built, carbureted 427). In addition to the 427, a 366-cubic inch (6.0 liter) version was produced for the commercial market. Both the 366 and 427 commercial versions were built with a raised deck, four bolt main bearing cap cylinder to accommodate an extra oil control ring on the pistons. Unfortunately, the raised deck design complicated the use of the block in racing applications, as standard intake manifolds required spacers for proper fit. Distributors with adjustable collars that allowed adjustments to the length of the distributor shaft also had to be used with 366 and 427 truck blocks.

Mark IV engines also found themselves widely used in power boats, a natural application for these robust power plants. Many of these engines were ordinary Chevrolet production models that were fitted with the necessary accessories and drive system to adapt them to marine propulsion. Mercury Marine, in particular, was a major user of the Mark IV in marine drives, and relabeled the engines with their corporate logo.

History 427
Chevrolet gave all 427 engines except the ZL1 a torque rating of 460 lb·ft (620
1966 1969 L36 4-barrel 10.25:1 390 hp (290 kW)
1966 1969 L72 4-barrel + solid-lifters, more aggressive cam and high flow cylinder heads 11.00:1 425 hp (317 kW)[7]
1967 1969 L68 L36 with 3x2-barrel carbs. 10.25:1 400 hp (300 kW)
1967 1969 L71 L72 with 3X2 barrel carbs. 11.00:1 435 hp (324 kW)
1967 1969 L89 L71 + aluminum heads; RPO L89 also applied to L78 "375 HP" 396 engine with aluminum head option. 11.00:1 435 hp (324 kW)
1967 1969 L88 Racing-spec cam, high-flow aluminum heads (casting #s varied by model year) and some upgraded, competition-grade parts 12.50:1[8] 430 hp (320 kW)[9]
1969 1969 ZL1 Aluminum block with open chamber "3946074" aluminum heads; cam even "hotter" than L88's; upgraded parts similar to L88's 12.00:1 430 hp (320 kW)
1970 1977(?) ZLX L88-ZL1 hybrid; iron block with aluminum heads 12.25:1 430(?) hp (321 kW)


454

The big-block was expanded again for 1970 to 454.2 cubic inches (7.4 L) with a 4.251 in (108.0 mm) bore and 4 in (100 mm) stroke. The 1970 Chevy Corvette LS5 version of this engine produced 390 hp (291 kW) and 500 lb·ft (680 N·m), and the LS6 engine was rated at 450 hp (340 kW). It has been suggested that the LS6 was substantially underrated and actually produced well over 500 horsepower (370 kW) as delivered from the factory, although there is no empirical evidence to support this claim. Indeed, the AHRA ASA Class record holding Chevelle LS6 for the 1970 season posted a best of season trap speed of 106.76 mph (171.81 km/h) "1970 ASA LS6 454 Records", which suggests something on the order of 350 "as installed" (SAE Net) HP for a 3,900 pounds (1,800 kg) car and driver combination. Indeed, SUPER CHEVY MAGAZINE conducted a chassis dyno test of a well-documented, well tuned but production-line stock 1970 LS6 Chevelle and recorded 283 peak HP at the wheels [5] - a figure that lines up quite well with the previously referenced 350 SAE Net HP figure.

A 465 hp (347 kW) and 490 lb·ft (660 N·m) version of the 454, dubbed LS7 was also designed but never went to production. However, a handful of LS7 intake manifolds were produced and sold by a few Chevy dealers as performance parts. The LS7 was later offered as a crate engine from GM and advertised at 500 Gross HP.

Power began falling off after 1970, with the 1971 LS5 producing 365 hp (272 kW) and 465 lb·ft (630 N·m), and the LS6 option coming in at 425 hp (317 kW) and 475 lb·ft (644 N·m). Only the LS5 remained in 1972, when SAE net power ratings and the move towards emission compliance resulted in to 270 hp (200 kW) and 390 lb·ft (530 N·m). The 1973 LS4 produced 275 hp (205 kW) and 390 lb·ft (530 N·m), with 5 hp (3.7 kW) and 10 lb·ft (14 N·m) gone the following year. Hardened valve seats helped allow these engines to last much longer than the earlier versions, even without the protection previously provided by lead from fuel. 1974 was the last year of the 454 in the Corvette though the Chevelle offered it in the first 1/2 of the 1975 model year. It was also available in the full size Impala/Caprice until model year 1976.

GM continued to use the 7.4 L (454 cu in) in their truck line, introducing a new Vortec 7400 version in 1996. GM also introduced the 7.4 L 454 EFI in 1987 (GEN IV 1965-1990, GEN V 1990-1995, and GEN VI in 1996); the GEN prefix was used since Ford Motor Company owns the Mark V naming rights since it was used on a Lincoln automobile between 1977–79), which was electronically fuel injected giving more power and torque. The 454 EFI version was rated from 230 hp (170 kW) to 255 hp (190 kW) and from 385 lb·ft (522 N·m) to 405 lb·ft (549 N·m) of torque. The 7.4 L 454 EFI was found on GM 2500 and 3500 trucks made in 1987, until replaced with the Vortec 7400 (GEN VI) in 1996.

1970–1976 Chevrolet Caprice
1970–1975 Chevrolet Chevelle
1970–1975 Chevrolet Monte Carlo
1970–1975 Chevrolet El Camino
1971–1972 GMC Sprint
1970–1974 Chevrolet Corvette
 
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