What is the difference between a shortblock and a longblock?
Both terms are used to refer to the engine, but what's the difference between them?
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tl;dr
In general,
- short block = block + rotating assembly
- long block = short block + heads
When talking short or long block, you are suggesting the completeness of the engine.
Basically, a short block will consist of the following:
- Engine block
- Main caps
- Rotating assembly
- Crankshaft
- Connecting Rods
- Pistons
- Rings
- Bearings (both rod and main)
- Freeze plugs
If the engine is an Overhead Valve (OHV) engine (ie: push rod engine) it will also include the timing chain and cam.
A long block consists of a short block, plus include:
- Heads
- Head casting
- Valves
- Seats
- Springs
- Retainers
- Keepers
- Rocker arms
- Push rods (if OHV)
- Lifters
- Oil pump
If the long block is of an Overhead Cam (OHC) configuration it will also include the timing chain/belt, and cam shaft(s).
The above is a general rule of thumb, as some engine rebuilders may consider things differently. Always confer with your engine builder to ensure you are getting what you think you are getting. Also, everything above also assumes the fasteners, such as if you have heads on the engine, it will include the head bolts. If you have the main caps on the block, it includes the main bolts, etc.
