I installed the flywheel today. I have an LS7 so I ordered an LS flywheel locating dowel and when I went to install it I realized that it was way too small. WTF? I have a built motor and it has a Callies DragonSlayer billet crankshaft with an LT, rather than an LS, bolt pattern. D’OH! Fortunately, I had ordered the flywheel with the correct pattern.
The LT is clearly designed to deliver more torque, it has an extra bolt and the flywheel locating dowel is significantly larger. The LS dowel pictured below is a GM Performance part and it looks like something from the Home Depot bargain bin.
Flywheel locating dowels; LT on left and LS on right
I tapped the dowel in with a brass hammer and noticed that it wasn’t centered between two holes. This meant that the flange on one of the swanky12-point flanged bolts wouldn’t clear the dowel. The solution was to chuck it up in the lathe and take 0.050” off of the flange’s OD.
Note that the dowel is closer to the bolt on the left whose flange has already been machined
50 thousands has been machined off of the left bolt’s flange