Yes it is a stock 4spd out of my 70 340 4spd Dart 23 spline. I called Brewers and asked them if you could do something to make it stronger and they told me even an 18 spline would not be that much stronger. I guess 3rd gear is the weak link but he said it will handle 600hp in stock trim and that it is a VERY STOUT Trans. He say's if you bank 3rd gear really hard that it could break.
I have 3.55 gears in it now and a brand new Nodular 489 case with new Sure Grip 3.91 set up, Big Yoke 7290 with the U Bolts to hold it down.
I am going to try it with the 3.55 gears and see how it acts. It should still pull it around pretty darn good with all that torque down low.
