How to choose long block core engines
Engines are sold for repair, originally the engines have been removed from use due to some defect. Often people ask what the problem is with them, sometimes the lifters are broken, sometimes just worn out, sometimes the whole cylinder needs drilling, sometimes rusted, camshaft worn out or even valves broken and much more. There are faults of all kinds, so be prepared to refurbish the engine and use machining services when needed.
So, what is promised then? The promise is that the engine can be restored. I also assist with spare parts according to what raw materials are in stock, to get a good start for each project.
If you come to pick up the engine yourself, you can always choose from the engines in stock. The oil pan and valve covers can be opened and the cylinders can be inspected with a boroscope. If you need shipping, it is also possible and I try to choose the best one from the stock, but the inspection is shallower than if you come to do it yourself.
So far, suitable engines have been looked at for hundreds of projects, and a suitable one has always been found. With a little research, you can usually find out why the engine was originally removed from use.
What is the difference between engines? When choosing an engine, you basically have 3 decisions to make. Do you want to save 50kg, do you want a 5.3l or 6l engine, and do you want more durable internals?
50kg can be saved by choosing an aluminum block, which is mainly interesting when axle masses are encountered or weight really matters, for example in drifting.
5.3l vs 6l is purely a question of money, 5.3l is cheaper but has less torque, but with a turbo you can get enough power. 6l gets more torque if the car weighs more, think of a full-size American car. With 6l, you can still choose whether you want a rectangle port or a cathedral port. Rectangle port is better and especially suitable for NA engines. Rectangle ports are found in 6l/6.2l gen4 engines.
Finally, you should know what kind of internals you want, gen4 engines have more durable internals and there are also improvements in the block, and you can tune it further without having to buy forged components.
So, in short, if you didn't feel like reading:
Cheapest - gen3 5.3l
Cheap with a turbo - gen3 5.3
Rich man's special - 6.2l gen4 alu
A lot of power on a budget - gen4 6l
A lot of power lightly - 5.3l gen4 alu
Torque on a budget - gen3 6l