Fill a large pot with enough oil to reach a depth of 1 inch and heat until it registers 375 degrees on a deep-fry thermometer. Working in 2 batches, fry the basil leaves until translucent and no longer bubbling, about 30 seconds. Using a slotted spoon, transfer to paper towels to drain; season with salt.
Preheat the oven to 425 degrees . In a 9-by-13-inch baking dish, spread the pancetta in an even layer and bake, stirring once, until slightly browned, about 25 minutes. Using a slotted spoon, transfer the pancetta to a plate. Add the tomatoes to the baking dish, stir in the garlic and season with salt and pepper. Bake until the mixture is slightly wet and the whole tomatoes have collapsed, about 15 minutes.
Meanwhile, in a pot of boiling, salted water, cook the pasta until al dente. Drain, reserving 1 cup pasta cooking water. Return the pasta to the pot and toss with the tomato mixture, olives and pancetta, adding some of the reserved cooking water to loosen as needed. Top with the fried basil.