Re: TFI and HEI what\'s the difference?
HEI is High Energy Ignition.
Brand name for GM's E-core coil ignition.
Rotor too thin and too close to the grounded internals of the distributor.
Coil in cap arrangment has a slew of problems getting spark energy to spark plugs where it belongs.
Good points are,
Male terminals on cap (look like spark plug terminals), instead
of Female terminals (socket type, collect crud, never seal and there has never been an acceptable connector made for them that doesn't loosen up almost immedately.)
Easy to install, although you should add a ground wire to the distributor housing and to the heads.
Add a power relay with 10 AWG. wire that comes directly from the battery or starter battery terminal.
TFI, Was Ford's idea... (putting the ignition module in the distributor)
Thick Film Intergration. It was a flop.
The TFI ignition system did produce two things that are very good... Ford FINALLY went to an E-core coil, and it is excellent.
Ford finally got away from the DuraSpark ignition module.
The TFI module was a flop, but they moved on.
Ford cap, cap adaptor, rotor, plug wires & E-core ignition coils will interchange with '78 to '90 Jeep distributors with
no modifications to the distributor or ignition module.
Only a coil connector is required.
All tune up parts, all can be done by beginners.
Serious increase in reliability, driveability, economy and emissions.