Thanks for the thoughts guys. I took a little more time to dig into this. Checked the cam timing, degree wheel and valve motions meet the spec sheet. Leakdown good, I needed to check this anyway, looks like the engine broke in well.

So in regards to timing, yes, was a good day! Dave I recall you suggesting and doing some research on a 98 vortec timing maps. I found that info and threw it in my spark table with some smoothing, note I don't have any added timing due to P.E. I have always been hesitant on too much timing based on the saying "it ran really good before it blew up"! I also think I was not advancing due to knock count activity and would appreciate some thoughts on from you. I am thinking most of these are erroneous, possibly some real.

I drove the vehicle after warming it up for about 1/2 hour, stayed below ~3500 rpm, the timing map really woke it up, low throttle opening and significant improvement in mileage. I got a total of 4550 counts. Reviewing the log in detail I found 599 instances of knock retard, 260 at 1 degree or more, 64 at 3 degrees or more, 2 at 22.5, 1 at 16, 1 at 40, I am thinking the higher values are erroneous data from the log and only occur at one discreet point, which is evident in the plot (attached). The high knock activity flag was present 24 times. Looking at the spark advance some of the values in the data skyrocket from 40-11548 degrees! I used the "wash and rinse" spreadsheet that I believe you put together, Dave, thank you. My timing table only advances up to about 36 degrees (attached), so anything larger is confusing to me.

In a nutshell it is a big step forward. I still need to check my VE tables and see if the "trough" has gotten better.
Thanks again for the thoughts.
Mark
knock retard.JPG
timing.JPG