wow...
4lo .... start in 2nd ....build some boost...leave the line..once at wide open throttle maually shift to 3rd..... as long as rpm's stay high, stay in 3rd... and if at the end of the track the rpm drop significantly, drop back to 2nd... done deal. tire pressure should be messed with as well. i asked this same question a while back, that is what i was told..i got 4th out of 21 in the modified class... im not saying its the answer, but it worked for me, considering i was the only one not hanging weight in the top 10. here's how it worked.
YouTube - BigR at AV Fair Diesel Pull