You will need to retain the clutch that will permit you to change the gears from one to the other smoothly.
In most conversions, automatic transmissions are discouraged. They are not used for various reasons. Mechanically, they are not energy efficient. If you use this type of transmission, you stand to incur energy losses. The loss will mean you will not get optimal performance with your car. Again you may damage your motor with the the automatic transmission. According to transmission experts, the automatic gearing depends on an idling engine to keep hydraulic pressure up. At a stop, the engine will stop running and thus lose pressure. You can overcome this with an additional pump but it all amounts to building up expense for the conversion.
If you are converting to an electric car, you will want to get a small sedan which have a manual transmission. This way you can be able to use energy efficiently. A sedan is also light in with and will not burden the engine with so much motive power.
The type of transmission yo choose will have an effect on your cars performance. Manual gearing is recommendable, especially those coming from smaller vehicles. You can be able to use an automatic transmission but will need to put in some add ons which can translate into higher expense.