I have a 727, not a manual trans in a 71' dart, complete interior, all stock body. mild 318. I've been racing street legal and mopar division for several years on an 8 1/4 with a dana cone sure grip carrier and 3:55 gear set. I've got hundreds of 1/4 mile passes/8-10, 000 street miles on the car with a very lead foot and lots of tire smoke. I even accidently threw the car in reverse one time with the pedal to the floor at about 30 miles an hour and spun the tires backwards enough to smoke show (oops. saw my dad and was going to "give him the pipes" LOL). So far the rear end has had no issues. The tranny on the other hand did not like it at all. I'm 3580# across a truck scale (several times) on the way to the track with a full tank of gas and a tool kit in the trunk. Got a fresh built 360, non stroker, about to drop in, should have approx. 100 more HP. Plan to race at least 15 weekends this year as well. We'll see what happens. Not sure if I would try it with a manual trans. Don't know if locker is more prone to break stuff. I roll off the line at around 1500 rpms at the track, then hammer it, because I know I am running an 8 1/4. Bracket racing don't care about your how fast your 60' is or your ET, just have to be consistent and have good reaction times.
I do have a dana with 410s setting on the side of the garage I need the disk brake set up for. There is a good chance I might need it this year. LOL
Other stock bodied/full interior car. 71 dart has 440 with an 8 3/4. 489 case, 3:91 gears. has many years of track time launching as hard as traction allows. Runs 12's with decent 60' times. Probably around a 100 passes last year. NO issues with rear except it chews up a lot of expensive street slicks. LOL
lots of guys running 3.91 to 4:56 and above gears, 11 and 12 second cars, with 8 3/4 rear ends at local track. running year after year. Only 1 that I know of is running a 4 speed. hopefully this is helpful to you in some way in your decision making processes.
