I'm sure there are plenty of you out there that have done one piece rear main seal stoker motors. My question is, where can you get the correct counterbalanced flywheel or flexplate for a stroker crank with the one piece seal crank flange? What balancer do I need? I just did a motor swap on a guys 98 K2500, and I get to keep the 5.7 Vortec motor that needs rebuilding. I was thinking about building a stroker motor for my 97 K1500 that is going to need a motor pretty soon (139K hard miles towing and plowing). Thanks for the info, guys.

You just use the stock ext balance flexplate.
The front will normally balance with one pc of Tungsten under about 1850 grams.
Or you could use a 400 damper.
This is with a Scat 5.7 rod crank

With the 6" crank you can internally balance it & use a neutral flexplate.

Mike, does the Scat Crank for the 5.7 rod have the 400-style crank snout, or is there a damper with the correct balance with the smaller 350-size crank snout?

Originally posted by caru68:
Mike, does the Scat Crank for the 5.7 rod have the 400-style crank snout, or is there a damper with the correct balance with the smaller 350-size crank snout? Snouts are all the same size & the dampers are interchangeable.
Differences are weight, timing mark & outside diameter.

Oops, I was thinking of the main bearing diameter. Thanks.

I used an Eagle 4340 crank in my one piece seal block (383) that was designed for use with 5.7" rods and internal balance. It turned out that the counterweights hit the pin bosses on the pistons. After modifying the counterweights (grinding) to clear, the engine still balanced internally without mallory. My machinist simply removed the balance weight from the flexplate and neutral balanced it, and I used the GM 8" balancer for a 350.