difference in R44T and R44TS spark plugs

[Custom 68]

Hey all like the title says? I was trying to get my newly rebuilt Fuel injected (TPI) 327 running. I had the usual unknowns of the new engine plus the fact I bought a used TPI. I then proceeded to cut the wires out I didnt need and spice some length to the 30 or so I did need. So you can see I was a bit leary about the new setup. Anyway a had a bad air intake temp sensor so it was running RICH it went down hill from there and couldnt get it started. I checked and replaced the necessay items. Once I finally checked the spark plugs for spark (had timing light on so there was fire to the plug) it had a very weak spark. I had just cleaned them (they were new prior to the rich run) to no avail. I grabbed my old ones sitting from the tear down a year ago and stuck them in. It now runs great!
Anyway my old ones were the R44TS the new ones were R44T. I was running HEI before and of course am now.
Could that have been part of the problem?
Thanks
DAve