Engine Blocks
Definition of short and long block
You can purchase an engine at various stages of it's development:
Block
All you get is the block and because they will look alike, care must be taken to correctly identify the correct size, as a 283ci block can easily be mistaken for one of its larger brethren.
In order to avoid buying a 283 block instead of a 350, you need to identify the casting numbers and be aware of the differences. Blocks are generally two bolt (hold the crankshaft to the block) or four bolt. For street use up to 400 bhp a two bolt block is more than adequate. For rodding, drag & race applications, where higher revs and increased bhp are required, a four bolt block should be used. Four bolts blocks are not as readily available and attract an increased price over a two bolt. Purchasing a block on its own is a good idea if you have damaged just the block of your existing engine, and wish to transfer over the parts. It is also for those of you that wish to build your own engine from scratch.
Short Block
A short block includes the bottom end of an engine, or the block, crank and pistons. It does not include the heads, manifolds, water pump, balancer, or the valve train.
These blocks appeal more to the experienced engine builder, as you need to be aware of the variations in performance / reliability when purchasing the top end parts.
With the availability of American engine parts in this country, there is a small price difference in purchasing a short block over a long one. If you are having your engine made for you, it makes sense to pay the extra and know that the right parts for your engine have been purchased and correctly fitted.
Long Block
A long block includes the block, crank and pistons, as well as the heads, manifolds, water pump, balancer and valve train.
Due to the various bore size of blocks available and the different types of camshaft, pistons, valve sizes, stroke, bore and compression ratios, many options are available. Achieving 350 bhp from a 350ci engine is easy if you have the correct engine variables in the first place. Without knowing your engines characteristics, you may find that you fall far short of the potential bhp & torque available from your engine.
Complete Engine or turn-key unit
To make a long block into a complete and working engine, you will require an inlet manifold, carburettor, distributor, alternator, spark plugs and leads.
Some people like to add these parts themselves, as it is relatively easy provided you have some experience with engines. You can research & choose the parts that you want, basing your choice on performance / looks or both. It also gives you the satisfaction of knowing you have had a part in the build of your own engine. |
