I just finished (well im never finished) MegaSquirting my 5.3 in my 65 chevy Pick-up. Here is a pretty good write up form a guy that dropped a 5.3 in a rx7. http://www.v8rx7forum.com/v8-rx-7-bu...tml#post411417
At first I had some issues with some noise and couldnt rev past 2500rpm the ignition would break up. Instead of inputting the crank signal directly to the cpu pin (like mobeythevan) I ran it through the opto isolator as per the write up in the MS2Extra documents and has helped ALOT!!!!!. http://www.msextra.com/ms2extra/MS2-Extra_LS1.htm
I still power the crank sensor with 5v. I still have some breakup up near the 5k rpm area but going to shield some wires and hopefully that will help.
Also I have tried the MS2extra beta11 and it seem to run smoother (everyone says that when they upgrade from ms1 cpu to the ms2 cpu) But I havenít been able to try it out yet since Iím not getting a tach out yet for my trans computer. Part of that could be im running 39lbs injectors (flex fuel motor) and it can control things with more accuracy. I will fix that soon and be able to give a full comparison.
So yes it's up and running with the LS1/genIII motors with the stock crank/ cam triggers and the stock coil packs.
One more installation note. You can power the coils directly from the led outputs and create one more output for the 4 pair of coils. You do not need to add the 4k7ohm resistor per the ms2 docs. also you can wire up your first pair of cyclinders up to output A (unlike Mobythevans's direction) you just have to move adjust the crank trigger menu alittle different
Here is a couple more theads to look at: http://www.msextra.com/viewtopic.php?t=25691 http://www.msextra.com/viewtopic.php?t=25285