Accel Super Coil & Tach
 

I'm running an Accel Super Coil 140003 on my truck. I'm about to dive into replacing the dash cluster with stock style gauges. I keep reading warnings not to wire up the tach on these to HEI systems. It seems odd to me because my 140003 has a place just for a tach wire and I've been running one of those old Harbor Freight jobs off it for years. What up with this? Is there something about old style tachs I need to know as in some kind of work around? They certainly can't be any less sophisticated than my Harbor Freight unit. In any case I'd really like to not smoke my new OE style dash cluster so any advice on this would be most appreciated.