This new update lets you swap any in-game engine to any car the same way as you could manually edit engine values previously! Not only that, but you can also put any in-game engine tuning parts in it, and there are A LOT of them! Keep in mind that there won't be any visual change or weight difference, just performance.
You equip it the same way as the engine value settings, in the Nitrous slot:
It is recommended to detune your engine to the default factory setup first before doing this as some swapped parts might potentially conflict with the original ones.
There are many engines for you to choose, all ordered based on the size so you can easily see which ones are bigger, also all have their manufacturer listed. Bigger engine usually means faster car, unless it's a Diesel engine (I put the letter D next to the size to indicate that it's a Diesel one), then bigger just means more torque (more hauling power or whatever). You can use the Diesel engines on gasoline-powered cars and vice versa, the type of fuel your new engine will run on only depends on what the previous one was running on. So you can swap a bus or truck engine into any car (it won't affect the weight or looks, just the performance.) If 2 engines have the same size, the one with more cylinders will usually be better, if both have the same then a more modern one (It is indicated which engines are modern in the selection), if both are from the same era then I put 1 word descriptions like "sport" or "offroad" so you can see which one will be more proper. Also some engines are listed as SOHC or DOHC, for your info the DOHC ones are faster.
Here is the list of all available engines (it's very long idk if you can read it):
The electric motors are not really electric motors but normal engines that behave like them, you can still tune them and all. Also there is the cannon 'engine' available that can be tuned as well.
After selecting one of the engines a new tuning slots will appear:
In the engine management, you can select any rev limiter or ECU available in the game:
They are sorted by RPM limit and the non-RPM-based ones are on the bottom.
You can also choose any intake:
The carburetor intakes are on the top and sorted by the amount of carburetors and barrels, more advanced intakes are lower. If you want to choose an intake that won't modify the engine performance, choose the 1x 2-barrel carburetor for carbureted engines, generic intake for more advanced ones, and modern intake for modern ETKs and the Cherrier (it actually gives negative power because choosing it normally means you are getting rid of the turbo).
You also have all long blocks available in the game - not so many:
You can also choose superchargers and turbos independently from the stock intakes.
Superchargers are separated between classic and modern ones, of course modern are better:
And there are also all the different turbos... A LOT. Some were so similar I made shared "generic" ones instead of 2 separate ones. You have both all the factory ones and all the race ones. It is indicated which ones are meant for Diesel engines and which ones are modern (so better). Of course there are also the Hirochi twin turbos, and the Gavril T turbochargers meant for heavy vehicles that add a lot of torque but not much actual power.
With this mod you can now reach 6000+ horsepower using technically only in-game parts! Have fun!