First figure out how much power you truck has. This may not be as easy as it sounds, because, unless you have had your truck on a dynamometer, there will be some guess work involved. It is important to get as close as you can. Many people don't realize that you can over-clutch a system. A clutch designed to hold 550 hp may not act right in a truck that only puts out 350 hp to the rear wheels. We often hear people say that they "might" add more power in the future. Realize that if you choose a clutch based on that, and you don't upgrade later, you might end up with parts you're not happy with.
Next. Decide what you want to do with your truck. Is it just a daily mode of transportation? Do you do any towing with it, if so, to what degree? Do you want to compete with it, if so how often? What size is your truck? Is it 2 or 4 wheel drive? Be specific. These are all important factors.
Here are some general rules
The hp rating of the clutch should match or slightly exceed the estimated hp of the truck
Any truck used for competition sled-pulling should use an SFI approved multi-disc clutch.
Trucks that regularly tow 15,000 lbs or more should use a double disc clutch designed for the street, regardless of the hp level.
Trucks that are above the 450 RWHP which are used primarily for towing should use a street double disc. A full metallic single disc clutch is likely to engage too aggressively, especially on 2WD trucks.
High torque clutches often incorporate metallic linings which may cause an aggressive engagement. This may be even more apparent when towing.
Performance or high torque clutches may feel, drive or sound different than the factory system.
Remember, when vehicles are modified beyond their factory specifications or used above the factory limitations, to the point where a performance clutch is necessary, things are going to feel different. By choosing the right clutch for your application, you can minimize these effects. However, some of the differences in how a clutch feels or sounds may be necessary to make the clutch hold and last.
Here are some unreasonable requests
My truck puts 800 hp to the ground and I drive it every day and I want a clutch that doesn't push hard.
My truck only has 400 hp, so I just need a single disc clutch, but I want to sled pull once in a while.
I pull 20,000 lbs every day but I can't afford a double disc clutch. How many miles do you think I can get out of a single disc clutch?
This is the last clutch I ever want to put in my truck.
You need to realize that each clutch has limitations and that clutches that are built to hold extreme horsepower may not be the easiest clutch to drive on the street every day. So, as I said before, you need to decide what you want to do with your truck and understand that you are responsible for some of the consequences of trying to do too much.
When you are buying a clutch, keep one thing in mind. No clutch is indestructible. No matter who made it or what it is rated for, you can destroy it in a hurry if you don't use it properly. So if you are careful when choosing it and reasonable when using it, you can get the most out of your clutch.