I called JB Conversions and they don't have anymore of the long input shafts. 86M1028 is right, the only option is to put a longer output shaft in the Turbo 400.
I haven't decided how I'm going to proceed yet. I don't want to do anything with the 400 that's in the truck now. I do have another 400 that I could build with the longer shaft so that might be an option. For now though, I'm taking a break from it!
I'm out of town right now, but can verify when I get home.
I know the short (round) & tall (figure
adapters (400/205) are the same length.
Im pretty sure shaft length is the same.
Your lowmax will work with your stock trans.
Obviously you won't have the full spline engagement
you would have with the long input but your short
input will give you about 3 & 1/2 inches.
I will verify this in about a week.
NOTE I'm building a
(1) 4l80/205 setup (none stock adapter)
(2) 4l80/203/205 lowmax
I have all the different trans/ t-case set ups & can measure them.