if u don`t live on a dirt or gravel road, I wouldn`t worry about it. I had a hemi w/o one for 14yrs., never had a problem w/ it. will help keep the convertor cool a little too.
Yeah there's no converter on a 4 speed. Much larger cover on a 4 speed too, leaves a good amount of flywheel exposed. I would worry about road debris getting sucked into the flywheel and clutch. Garbage bag, chunk of wood, damn near anything that went under the car could get wrapped in. I know a guy that ran over a pillow one time, just a pillow. The u-joints on the driveshaft grabbed the pillow case, wrapped it in and it displaced the pinion seal out of the differential. Drained the diff pretty quick. Getting something like that wrapped into the flywheel and clutch could make for some issues.
