thanks for the info I have 4 l99 all run well just they have been pulled out and replaced with the 5.7 lt1 so I have an idea ill make some good gas milage engines for my offroad buddies on budget buthe tunes are all different tire size transmissions gear ratios ahh and the dreaded map tables they all have very low rear gear ratios that makes them littlte motors with the right torqe and enough power.so far the ones I have installed are still running a year later with a lot of abuse thrown at them as long as you have a good radiator and fan even in this weather of 100 degrees plus everyday they still stay cool enough to run daily.I live 40 miles from death valley.IM going to the junk yard today to see if ican pull some old caprice 4.3 pcms when I get them and bench test and tune ill probably get enough info to build a new bins.if they work ill post them if that's alright.