If you’re going to fabricate it, utilize the measurements from your vehicle and leave what someone told you out. If I were going to fab one I suppose I’d get the brackets I planned to use, or fab them and measure the remaining span. V6 can be straight but there’s clearance factors for ps reservoir, ac plumbing, and a couple wire harness studs that need to be removed.
On v8 or some older v6s the alternator will be in the way.