Big Block Chevy Firing Order [2024]

In 1955, Chevrolet debuted their widely successful small block V8 engine, but the automaker required an engine with a higher displacement to compensate for higher power needs for its medium-duty trucks and the heavier automobiles that were still in the concept stage at the time.

The normal displacement of the large block ranged from 348 cubic inches being 5.7L when it was first introduced in 1958, all the way up to 494 cubic inches being 8.1L when it reached its maximum capacity.

Big block chevy firing order

The Firing order for Big Block Chevy is 1-8-4-3-6-5-7-2.

The explanation for big block chevy firing order

When the piston is at Top Dead Center on the compression stroke of a big block Chevy engine, the distributor’s blade should be aligned with the number 1 spark plug contact in the distributor cover. This is done in accordance to get the correct firing sequence for the engine. This step is used to ensure that the spark plugs are lit in the appropriate sequence.

There is a significant divergence between the firing sequence of a small block and a large block Chevrolet engine, but otherwise, the two have a lot in common. The large blocks each include an additional cylinder. This indicates that the sequence of fire will be 1-8-4-3-6-5-7-2.

That indicates that the cylinder with the number 1 is the one that ignites first, followed by the cylinder with the number 8, then the cylinder with the number 4, and so on. The fighting order for all big block chevy engines is the same.

This firing order applies to:

  • 366 Chevy
  • 396 Chevy
  • 402 Chevy
  • 427 Chevy
  • 454 Chevy
  • 502 Chevy

Torque Specifications

Fastener Type Torque Specs
Main Cap Bolt (396-427, 2-Bolt) 95 ft.-lbs.
Main Cap Bolt (396-454, 4-Bolt, Inner and Outer) 110 ft.-lbs.
3/8 in. Connecting Rod Bolt 50 ft.-lbs.
7/16 in. Connecting Rod Bolt 67-73 ft.-lbs.
Cylinder Head Bolts, Long 75 ft.-lbs.
Cylinder Head Bolts, Short 65-68 ft.-lbs.
Screw-In Rocker Arm Studs 50 ft.-lbs.
Intake Manifold Bolts (Cast Iron Head) 25 ft.-lbs.
Oil Pump Bolt 65 ft.-lbs.
Cam Sprocket Bolts 20 ft.-lbs.
Harmonic Damper Bolt 85 ft.-lbs.
Flywheel/Flexplate Bolts 60 ft.-lbs.
Pressure Plate Bolts 35 ft.-lbs.
Bellhousing Bolts 25 ft.-lbs.
Exhaust Manifold Bolts 20 ft.-lbs.

Chevy small block and big block cylinder numbers

You may find the same order of cylinder numbers in any SBC, such as one with the numbers 302, 305, 307, 327, 350, 400; and in any BBC, such as one with the numbers 348, 366, 396, 402, 409, 427, 454, 502; and so on. This specific sequence is necessary to identify the cylinder after the vehicle has been released from the manufacturing facility

Check Out Firing Order of 8 Cylinder Engine

Firing orders for similar vehicles 

  • Dodge V8s: 1-8-4-3-6-5-7-2
  • Pontiac: 1-8-4-3-6-5-7-2
  • Rover V8: 1-8-4-3-6-5-7-2
  • Toyota UZ engine: 1-8-4-3-6-5-7-2

What is the difference between small block and big block firing order?

The firing order for a small block Chevy engine is 1-8-4-3-6-5-7-2, whereas the order for a large block Chevy engine is 1-8-4-3-6-5-7-2. The most obvious distinction between the small block Chevy firing order and the large block Chevy firing order is, of course, the size disparity between the two engines.

The dimensions of a small block Chevy are generally more compact than those of a large block Chevy. Because of this change, the small block Chevy firing sequence will have less punch but better efficiency when it comes to fuel consumption. The firing sequence for the big-block Chevy will provide more power, but it will also demand more gasoline.

The placement of the distributor is the primary distinction that separates these two firing orders, in addition to their relative sizes. The distributor for a big-block Chevy engine is normally positioned in the rear of the engine, but the distributor for a small-block Chevy engine is generally found in the front of the engine.

Check out Straight 6 Firing Order

What is a big block chevy 4-7 swap?

The firing sequence of a big block Chevy engine may be changed. The big block firing order swap is done for increased ride comfort. The 4/7 cam is responsible for the modification of the firing sequence of the engine.

It does this by moving the power stroke of cylinder 4 to the position formerly occupied by cylinder 7, and vice versa.1-8-7-3-6-5-4-2 is the new firing order for a standard Chevy. The purpose and result of the big block firing order 4-7 swap are Engine smoothness is believed to be improved as a result of the new firing order.

Try Inline 4 Firing Order

How to: Small or Big Block Chevy Firing Order Explained

Jake Mayock