What was your a/F and timing? Knock and melted pistons is usually too much timing.

For 6 lbs you can get away with 20-25 degrees of advance at WOT. A/F should be 11.5:1 for a nice safe tune.

If it was injectors or a pump, you'd see it in the a/f. Rule of thumb in my book us if you see 12 on a wideband let out. Hard to tell 12.1 to 12.9 when you're racing or doing burnouts, hence why I like 11's.

You shold also be fine on 87 with 6 lbs. That's a fart in the wind.

 

I agree with others , it's 99% prob your tune.

First , Blackbear Justin is well known reputable tuner who has made lots of people happy over the years I've read/heard reviews on his tuning .

Second , People do NOT understand what all is involved with tuning a vehicle let alone tuning a modified Forced Induction Vehichle . Scan, Log , adjust , Scan , Log , Adjust , Scan , log , adjust , Scan , log , adjust , Scan , Log , adjust , Scan , Log , adjust . ( years have past ) Scan , Log , adjust , Scan Log , Adjust .

If your picking up what I'm Layin , you are Never done completely tuning a Vehicle , there's always something tiny depending how picky you are .

It's hard to get a spot on tune to your liking when someone isn't actually in your vehicle feeling it out and adjusting the tune . With forced induction you should have a live in person tune by a reputable person if you have that at your disposal . And you should have all the necessary gauges / parameters monitored and watch them carefully .

And lastly unless you sent a sample of your " bad fuel" to a lab , it's BS to blame that issue on poor fuel , like said you can tune your vehicle to run on any octane.

 

BB is known for bolt on trucks and smaller mods


Look at the fastest names around and see who is doing their tuning....In my personal experience being at these truck races BB isn't one of them

Just something to think about, not knocking the guy but stating facts

 

I hope you figure it out, but it looks like it was partially your fault for not looking at the injectors. Also if they were the size you say (8.1 injectors) you should have still had a lean reading on your wideband..