Re: Programmable HEI
 

This Progression Ignition, still going good for you? Do you believe the MPG has improved over whatever you used before?

Somehow today I stumbled on thinking about this unit again. What I been focusing on is the adaptive timing for the idle, like you mention when going from Park (or neutral) into drive and it keeps idle. I also believe this works when the AC turns on. From your signature you have AC - does the HEI deal with that too? Any idea if that is bad for the engine to be bumping the timing all around to keep stable idle during the cases (in drive, in park, AC on/off)? Heck, how does it know you are in idle or not?

Also, do you have tach in your cluster too? I believe it has a wire for that but currently the dash (I upgraded to a stock one in my cluster) and it connects to the coil.

Sorry for the 1 zillion questions, hope you don't mind them!

Re: Programmable HEI
 

Another option is the MSD 6AL with integrated timing. I have been running one for about 5 years now. It also has captive discharge which is nice with bigger cams for cleaning up the idle.

Any of these setups should work the same way. Lock out the distributer and then set it at max timing. The box then sees the signal and delays the signal which gives the motor less timing. Hope that makes sense. With this timing modulation there should be no negative effect to the motor long term however if the electronics failed and it did still run you would have hard starting from maxed ignition timing due to the distributer being locked out.
Speaking only for the MSD you can add a MAP sensor and use it to set up a vacuum advance curve. Since you ask about AC I am betting this function could be made to kick the idle up since the compressor load would be seen as a load, ie vacuum drop.
The only catch to these systems that I have seen is there are only so many degrees of adjustment between all the settings for timing range together. It doesn't matter if you use them all in one table or two. I don't remember the range but do remember that 50 degrees total, vac and mechanical advance, isn't going to work with low base timing of something like 4 degrees.
One thing that I really like is that my motor needs alot of base timing due to rhe cam. I am between 20 and 24 degrees. The MSD let's me ramp that in so I have effectively 0 degrees timing than ramp in the base timing by 600 RPM. This makes cranking easier and less chance of engine kickback on the starter. All the timing is done in simple tables via laptop. It also has several Rev limiters built into along with some racing functions that I don't use.

Re: Programmable HEI
 

Well, I ordered one after getting a email back from them, I was real impressed how quickly the responded to my web query!

Might as well post my Q/A here.

1. any problems with the Chevy 72 Tach where the wire goes to distributor coil?
   
   Quote:

   Theodore@Progression: No problems with the tach. Use the same connection to the coil negative. Don't use the grey tach wire on the distributor.

2. I believe I should be looking at the CHEVY SMALL & BIG BLOCK V8 SMALL CAP DISTRIBUTOR W/FIXED COLLAR, black, and with female wire connectors.
   
   Quote:

   Theodore@Progression: Yes

3. Do I need a new coil and/or wires? Mine is the PerTronix 45011 Flame-Thrower II Coil 45,000 Volt and their PerTronix Flame-Thrower 7mm Stock Look Spark Plug Wires.
   
   Quote:

   Theodore@Progression: You don't need a new coil or wires.

4. One thing I am very interested in is the timing that happens at idle and when the A/C turns on/off. I think I saw or read that your distributor increases the timing somehow to keep the idle steady? How does that work or am I misunderstanding it.
   
   Quote:

   Theodore@Progression: The timing table is setup such that, when at idle, if the RPM drops the timing will increase. This will not eliminate the RPM drop caused by shifting from Park into Drive or turning on the A/C but it will make it more manageable. The increased timing produces more torque to compensate for the increased load on the engine from the torque converter and the A/C compressor.

Re: Programmable HEI
 

I see by your last thread you ordered one. Mine is working great I have a repo factory tach and it works great. I also use the lock feature when leaving my truck in a parking lot along with a Club.

Re: Programmable HEI
 

ah, I forgot about that feature, locking it - I am going to LOVE having that option!

Thanks tdangle