The Chevrolet Big Block V8 Engine – The Rat Motor

The Chevrolet Big Block V8 Engine – A Brief History and Evolution of The Chevy Rat Motor

The Chevrolet Big Block is one of the most familiar and long-running Big Block engines. Nicknamed the Rat Motor, the Chevrolet big block’s long history started in 1958 with the introduction of Chevy’s all-new 348 cubic inch engine. Chevy’s big-block had a long run with variations up to 572 cubic inches and was produced well into the 2000s.  Big Block engines were installed in many muscle cars including Camaro, Chevelle, Nova, Impala Corvette, and more. Amazing power, high revving capabilities, and brute force from these engines have earned them a place in automotive history.

Chevrolet Big Block Engine Identification – Casting Numbers, Date & Engine Codes

Chevrolet Big Block Heads – Casting Numbers and Specifications

Mark I W Series

The first Chevrolet Big Block V8 engine was the W Series. Produced from 1958 to 1965, the engine had W-shaped valve covers due to its offset overhead valve design. Mark I engines were used in Chevy cars and trucks and were available in three displacements, 348 cubic inches, 409 cubic inches, and 427 cubic inches.

 

The 396ci Chevrolet Big Block Engine

396 Chevrolet Big Block V8 Engine

 

Mark I W Series Horse Power Ratings

Cubic InchesBore and Stroke Gross Advertised PowerModelCarburetionProduction Years
13484.125 x 3.250250 hp (190 kW)Turbo Thrust4 Barrel1958-1961
23484.125 x 3.250280 hp (210 kW)Super Turbo ThrustTriple 2 Barrel1958-1961
33484.125 x 3.250305 hp (227 kW)
43484.125 x 3.250315 hp (235 kW)
53484.125 x 3.250320 hp (240 kW)
63484.125 x 3.250335 hp (250 kW)
73484.125 x 3.250340 hp (250 kW)
83484.125 x 3.250350 hp (260 kW)
94094.312 x 3.500360 hp (268 kW)4 Barrel Carter1961
104094.312 x 3.500380 hp (283 kW)4 Barrel Carter1962
114094.312 x 3.500409 hp (305 kW)Dual 4 Barrel1962
124094.312 x 3.500425 hp (317 kW)Dual 4 Barrel1963-1965
134094.312 x 3.500340 hp (254 kW)4 Barrel Rochester1963-1965
144274.312 x 3.650430 hp (320 kW)Z111963
154274.312 x 3.650575 lb·ft (780 N·m)Z111963

 

Mark II

The Mark IIs were race-only engines produce only in 1963. Variations of the Mark II included 396, 409, and 427 cubic inches and included aspects of both the W-series and the Mark IV engines.

Mark III

Never Produced By Chevrolet.

The Chevrolet Big Block V8 Engine 427 ci

Chevrolet Big Block V8 Engine 427 ci

Mark IV

The Mark IV engines shared many dimensions and features of the W series, but to improve higher RPM performance a new redesigned conventional wedge shape combustion chamber was used, the valve angle was changed, and the spark plugs were also repositioned.

 

Mark IV Series Horse Power Ratings

Cubic InchesBore and StrokeGross Advertised PowerModelCarburetionProduction Years
13964.094 x 3.760360 hp (270 kW)L344 Barrel1966-1969
23964.094 x 3.760325 hp (242 kW)L354 Barrel1965-1969
33964.094 x 3.760375 hp (280 kW)L374 Barrel1965
43964.094 x 3.760265hp (198 kW)L662 Barrel1969
53964.094 x 3.760375 hp (280 kW)L784 Barrel1965-1969
63964.094 x 3.760425 hp (317 kW)L78 Corvette4 Barrel1965-1969
74024.124 x 3.760330 hp (250 kW)LS34 Barrel1970
84024.124 x 3.760300hp (220 kW)LS34 Barrel1971
94024.124 x 3.760240hp (180 kW)LS34 Barrel1972
104024.124 x 3.760375 hp (280 kW)L784 Barrel1970
114274.250 x 3.760390 hp (290 kW)L364-barrel1966-1969
124274.250 x 3.760425 hp (317 kW)L724-barrel1966-1969
134274.250 x 3.760400 hp (300 kW)L68Triple 2 Barrel1967-1969
144274.250 x 3.760435 hp (324 kW)L71Triple 2 Barrel1967-1969
154274.250 x 3.760435 hp (324 kW)L89Triple 2 Barrel1967-1969
164274.250 x 3.760430 hp (320 kW)L881967-1969
174274.250 x 3.760430 hp (320 kW)ZL11969
184274.250 x 3.760430hp (3210kW)ZLX1970-1977
194544.250 x 4.000390 hp (291 kW)LS54-barrel1970
204544.250 x 4.000 450 hp (340 kW)LS64-barrel1970
214544.250 x 4.000465 hp (347 kW)LS71970
224544.250 x 4.000365 hp (272 kW)LS51971
234544.250 x 4.000425 hp (317 kW)LS61971
244544.250 x 4.000270 hp (200 kW)LS51972
254544.250 x 4.000275 hp (205 kW)LS41973-1976
264544.250 x 4.000 235 hp (170 kW)EFI1987-1990

 

The Chevrolet Big Block V8 Engine 454

Chevrolet Big Block V8 Engine 454 ci

The Chevrolet Big Block V8 Engine 572 ci

Chevrolet Big Block V8 Engine 572

 

 

 

 

 

 

 

 

 

 

Generation V

In 1991 GM changed the designation of big blocks to “Generation V” due to the fact that Ford was using the “Mark” name in some Lincoln car models. Significant changes and upgrades were made to the new Generation V Big blocks. The main oil galley was moved, a new non-adjustable valvetrain, new one-piece rear main seal, and all blocks came with 4 bolt mains. Displacements available were the 454, 502, and the monster 572 cubic inches only available aftermarket through the GM Performance Parts division.

 

Generation V Series Horse Power Ratings

Cubic InchesBore and StrokeGross Advertised PowerCarburetionProduction Years
4544.250 x 4.000255 hp (190 kW)EFI1991-1996
5024.466 x 4.000338 hp -600 hpEFI1991-1996
5724.560 x 4.375620 hp – 720hp1998

 




 

 

The Chevrolet Vortec 7400

Chevrolet Vortec 7400

 

Generation VI

For Generation VI the big blocks were upgraded with a new hydraulic roller cam, a new multi-port fuel injection and were now called the Vortec 7400. The Vortec engines gave slightly more power and better fuel economy.

 

VI Series Horse Power Ratings

Cubic InchesBore and StrokeGross Advertised PowerModelCarburetionProduction Years
4544.250 x 4.000290 hp (216 kW)Vortec 7400 L29MPFI1996-2000
4544.250 x 4.000290 hp (216 kW)Vortec 7400 L21MPFI1998-2001

 

The Chevrolet Vortec 8100

Chevrolet Vortec 8100

 

Generation VII

The Generation VII Vortec 8100 was designed with an all-new iron block and heads. Changes include symmetrical intake ports, new firing order, 18 bolt heads, and longer connecting rods.

 

Generation VII Series Horse Power Ratings

Cubic InchesBore and StrokeGross Advertised PowerModelCarburetionProduction Years
4964.250 x 4.370340hp to 550hpVortec 8100 L18MPFI2001-2009

 

Chevrolet Big Block Bore and Stroke

Engine Bore StrokeDisplacement
3663.935″3.760″365.8″
3964.094″3.760″396.0″
4024.125″3.760″402.0″
4274.250″3.760″426.0″
4544.250″4.000″454.0″
5024.468″4.000″501.7″

 

Other Chevy Big Block Info

Chevy Big Block

Chevrolet Big Block Engine Identification – Casting Numbers, Date & Engine Codes

Mark IV Chevrolet Big Block Heads

Chevrolet Big Block Heads – Casting Numbers and Specifications

3963569 Chey Big Block Aluminum 4 Barrel Intake Manifold

Big Block Chevrolet Engine Intake and Exhaust Manifolds Info and Casting Numbers

You May Also Like

 



Facebooktwitterredditpinterestlinkedintumblrmail

Trackbacks & Pings

  • Garaged 41 Years! 1965 Chevrolet Impala SS :

    […] the hood to reveal those wide valve covers makes for potent medicine among fans of the “Rat Motor.” If everything is original, the Powerglide makes this a 325 HP version, not the wicked solid-lifter […]

    9 months ago

Leave a Reply

Your email address will not be published. Required fields are marked *

%d bloggers like this: