Preheat oven to 400 degrees F. Peel away the dry outer layers of skin from garlic bulbs, leaving skins and cloves intact. Cut off the pointed top portions (about 1/2 inch), leaving bulbs intact but exposing the individual cloves (see tip, page XXX). Place the garlic bulbs, cut sides up, in a 1- to 1-1/2-quart casserole. Drizzle with about 1 tablespoon of the olive oil. Cover casserole. Arrange peppers, cut sides down, on a foil-lined baking sheet; brush with remaining olive oil. Bake garlic and peppers about 40 minutes or until pepper skins are charred and cloves of garlic are soft. Cool garlic on a wire rack until cool enough to handle. Pull up sides of foil and pinch together to fully enclose the peppers. Let peppers stand 15 to 20 minutes or until cool enough to handle. When peppers are cool enough to handle, peel off skins and discard. Chop peppers; set aside.
Remove garlic cloves from papers by squeezing the bottoms of the bulbs. Place garlic cloves in a food processor. Cut peeled tomatoes into chunks and add some of the chunks to the food processor with garlic. Cover and process until chopped. Transfer chopped garlic and tomatoes to a 7- to 8-quart nonreactive heavy pot. Repeat chopping remaining tomatoes, in batches, in the food processor. Add all tomatoes to the pot.
Add brown sugar, salt, vinegar, and black pepper to the tomato mixture. Bring to boiling. Boil steadily, uncovered, for 50 minutes, stirring occasionally. Add chopped, peeled peppers to tomato mixture. Continue boiling for 10 to 20 minutes more or until mixture is reduced to about 11 cups and reaches desired sauce consistency, stirring occasionally. Remove from heat; stir in basil and assorted herbs.
Spoon 1 tablespoon lemon juice into each of six hot, sterilized pint canning jars. Ladle sauce into jars with lemon juice, leaving 1/2-inch headspace. Wipe the jar rims; adjust lids and screw bands. Process filled jars in a boiling-water canner for 35 minutes (start time when water returns to a full boil). Remove jars; cool on wire racks. (See "Canning Basics," pages XXX-XXX.)