Actually not true. The 6 is the number of counterweights.

Here is how that part number breaks down:

383 is obvious
4150 stroke
J is main journal ( Chysler Hemi)
C is 2.200 rods
6 is counterweights
F is forged crank

What K1 and Molnar ( Molnar used to BE K1) did, was use the prefix " 426" for any BBM crank with 8 bolt flange, and " 440" for any crank that was 6 bolt flange.Since Wiseco bought out K1, maybe they made some changes in that regard.

383-4150TC6F used to be the old K1 part number. T standing for 383/400 BBM, more so for counterweight dimensions.

I will try to get ahold of Molnar today and get an answer. I was pretty sure the old K1 383/400 WERE 6 bolt. Perhaps that has changed as mentioned. I have been trying to get a few of these guys to get more 6 bolt cranks, as many people have exisiting 6 bolt parts, and to be honest, there is no big gain in the 8 bolt style for most applications anyhow. It was from the Hemis years ago, and everyone simply stuck with it because they felt the 8 bolt Hemi pattern was superior. I have still yet so see anyone tear 6 bolt outta the crank flange,...