Here are the raw materials we got from Dr. Gas. We used 3-inch aluminized mild-steel oval tubing, which does not have the same cross-sectional area as 3-inch round tubing, but Dr. Gas deemed it to be plenty for our 560hp, 408ci small-block. Note that the photo includes two 60-degree oval tubing bends, which were not needed. Should your project call for them (part No. OB3360) they are $57.95 each.