I feel like the aftermarket stuff was engineered stupidly sometimes. My Edelbrock ProFlow 4 system had an issue with the heater outlet fitting and the fuel line to the fuel rail trying to occupy the same space using the fittings that Edelbrock supplied. I ended up having to get a 90* fitting for the heater outlet and a banjo bolt for the fuel line. $50 worth of fittings to fix their mistake on clearence. Makes a person wonder if they even tried to install the thing and run it in a street vehicle with a heater. The ECU also does not have any kind of IAC compensation for the ac compressor. Everytime the ac cycles the idle dips or spikes and the engine surges while the IAC hunts to find its new position. Same goes for when you put the transmission into gear, especially reverse. When I find the time and motivation to do it, I will be configuring a clean, spare LS harness I have to run it with a P59. I put a spare 24x reluctor in that engine when I built it. When I swap the engine management, I will probably pull the TH400 and put a 4L80E in its place.