I'm still sorting out issues with my 540. I got it t run pretty good with a borrowed HEI distributor(no tach drive). Adjusted the AF mix on the Quick Fuel SS850 with an Innovative Wideband Meter. Initially it was rich or very rich at all rpms and loads. I ended up installing 0.0345 IFRs instead of the 0.036 stock IFRs. Also went to 0.073/0.79 from the 0.080/0.086 stock jets. Highway cruise was around 14:1 AF mix. Ran great at WOT and would melt the 275 tires in 2nd gear.

The problem is I want to run my TI distributor and maintain a somewhat stock looking engine. I don't like the HEI look and hate not having a tach. Between the tuning with the HEI distributor I installed the TI unit and the car ran like crap and fouled plugs. I ended up getting a new board because when I tested it, the voltage at startup didn't increase like it is supposed to. Also installed a new stator/magnet inside the distributor. The coil was replaced (correct from Zip) several years ago and probably had 500 miles on it. Eventually the car died and left me stranded until it cooled off- thinking bad coil. I ended up buying a coil from TI specialties ($$$!) and it solved the stalling problem. But now, I'm getting a steady miss at 2500 rpm, the AF meter shows 16:1, and the spark plugs also show lean. Timing is set all in 36 degrees at 2500rpm with vac advance plugged. I don't see why it would suddenly be lean. I checked for vacuum leaks and can't find any. Plugged the headlight wiper door accessory port too.

I'm not sure what to do at this point. Put the original IFRs and jets back in the carb and see what happens? I can put the old stator/magnet back in but the old board I know is bad on the start circuit. Maybe just punt and get a new HEI that has a tach drive.

Any help or test procedures are appreciated.

 

How about a MSD tach drive distributor? You can run a GM style socket cap on it (I have one on my own car).....and fits inside the shielding. Only downside is it has to have a box.
I am not a fan of the GM TI system.....too old and fidgety, better left for restorations.

Jebby

 

Wass your car originally equipped with the TI system? If not, you cannot just wire it up to the existing 'power' wire [which went to the coil]. That wire has required resistance for a "points" car. My suspicion is that you are not getting adequate voltage to the TI unit. Do a little more research on the differences between TI and points ignition wiring.

If your car IS a K66 vehicle, the issue is most likely due to some wiring fault or some issue in the TI box. Also, the TI coil is different from an HEI coil. The HEI coil may be too "hot" for the TI box.

 

The K66 is original to the car. I've installed a new amplifier board, magnet/stator, ti wiring harness, plug wires and cap (two sets) and a properly functioning coil recently. The original board was replaced in the early 90's, original coil mid 90's with an MSD Blaster. Got a correct appearing coil from Zip a few years ago, Genuine GM Restoration Part! made in China. Once warmed up it started misfiring and eventually shut off. Probably led to the demise of my 427.

Looks like the MSD 6AL box would be the first step if I cant find the problem. Per installation instructions and other posts the MSD box works fine with a GM TI distributor. This weekend I can go back to the original jetting, check wire resistance again, etc. At this point I don't know which, if any, of the TI components are bad. It could still be a mixture or timing problem.

 

For testing purposes, you can wire in a HEI module in place of the TI Amp. This eliminates the TI Amp and all the TI wiring, as you are only using the Dist pickup and Ign coil from the original TI setup.
If interested, I can supply a wiring diagram.