Hey Fellas, I rebuilt the 350 in my 94' Chevy C2500 about a month ago. It runs great! I do have a low idle issue though. So, I decided to venture into this world and ordered an ALDL cable which should arrive tomorrow. I downloaded WinALDL to my laptop. I'm not yet familiar with anything you guys talk about so I'll just shoot the numbers and hope you know what I'm talking about. My ECU #16205995, BLHH. I believe the "mask" (I think that has something to do with the program) is $0D. Although I have a custom prom the one that came out is a 27C512. My truck has the 12 pin connector OBD1. I just want to see what's going on behind the scenes while driving, and figure out my low idle. My vacuum is where it should be with the cam I installed at 18" at idle in park. My timing is 4* advanced. My fuel pressure is set at 16psi. I have a new IAC valve, and just about every other sensor is new and I've checked them with a multi-meter for voltage from the connector and resistance at the sensor. All good! My idle is fine in park, about 800-900 RPM's (that's IF my Sunpro Tach is reding the HEI correctly), trouble is once it's warmed up, in gear, and I put a load on it with power steering, A/C, etc. it falls to about 200-300 rpm. My battery voltage is low at that point as well, so, I'm wondering if maybe I bump up my alternator amps, (the battery tests good), it will help get the signals back to the ECM or whatever. I AM running an MSD CDI box, Stereo amplifier, and heavy duty headlight harness directly off the battery and that MSD alone needs a constant 5-6 amps to function correctly. Also, should I run something other than WinALDL? Not that I'll be able to understand it! Thanks!