The OBD II 2001 ~ 2002 '0411 PCM Express Van timing is referenced off the MAF sensor. I don't think it's really going to be apples to apples if trying to get an OBD II Vortec timing table to work with the '7747. The timing table I posted was tuned with a knock sensor, so it's going to be very close for another Factory Stock L31 using TBI. Just a caution, don't use the timing table I posted without a knock sensor!

dave w