[Ronbo]

Actually the duty cycle should be about 20~35% (on or 12v time) to properly simulate an ignition system. Dwell for those that remember this...

Since ignition systems don't produce true square waves (sloping transitions and ringing from the coil) they usually utilize overdriven amp stages for wave shaping as well as low-pass filtering.

Look at a car on a scope sometime, you'll see what the waveform looks like.

Also I would advise using a linear power supply not a switcher supply as the switchers can produce noise at certain load levels. (Look for a supply that uses a transformer) Weight/size is a good indicator of a linear supply. (transformers are heavy/large) Or just use a battery.

The Heathkit stuff was pretty good usually, but since they were kits you never know how poorly they were assembled by the "hobbyist", the plus side is if it has all the manuals, schematics should it need repair.

Wavetek made some pretty decent affordable generators... Have some WD-40 handy to spray the scratchy pots and switches. Don't laugh, this stuff worked wonders on Motrac heads in concrete trucks. (Old Motorola radio tech here)