ok, say you have a 150 foot straight and the motor is all the way up to temp already and you come to a stop then go wide open. Is the motor taking off fast with no hesitation and reaching max rpm about 3/4 way down the straight?
Or do you have to kind of baby it to get going and then when is wide open it never really cleans out and starts to scream. If the motor is way rich on top it will sound like the motor is really blubbery and never really make a whole lot of rpm. That will also cause it to die. It's basicly hydro locking.
If the motor sounds really blubbery and is smoking really bad when wide open then try turning your hs in about 2hrs run it some more and try going wide open if the motor still is not cleaning out and making full rpm by 100-120 feet lean the hs 1 hr at a time till it cleans out and makes good power. Then fine tune with your ls.
You always tune your motor for the track your on. Tune the motor so the it cleans out about 3/4 way down your longest straight and tune the ls so that after a wide open run you can stop the car and it shouldbe able to sit there and idle for 15 seconds or so before you start to hear the crank case fill up and make the motor sound kinda like a girggle.
Just keep an eye on your temps and remember you should always set your hs first then your ls.
Hope you get it figured out.