I'm sure this topic has been covered several times, but I wasn't finding what I wanted in a search. I saw an ad in Hot Rod for Crane HI-6S and HI-6 ignition boxes that come with free LX91 and LX92 coils respectively. The HI-6S is an inductive discharge box, and the HI-6 is CD. 1. What is the difference between these two? I think the inductive gives one sustained spark, while the CD gives pulsatile sparks--is this right. 2. I'm planning on rebuilding my LG4 using 58cc heads with 1.94/1.50 valves, a Comp Cams XE249 cam, and Hedman shorties. Would I benefit from this ignition box, and if so, which one would be better? (I'm still using stock CC q-jet and distributor.) 3. Are the coils that come with these in-cap styles, or external? Thanks, Eric

inductive storage ignition - this is what factory cars use. it is made for low rpm usage. it stores energy and sends it to the spark plug as needed. the problem is, it is slow at building energy. so, it is ineffective at high rpms.

capacitive discharge - opposite. charges up very quickly. problem is at low rpm it gets overheated from holding the charge until needed. that's why they say you cannot use a cd coil on street cars. overheat and burnup the coil.

now the cd boxes sometimes are not compatible with stock or inductive storage coils. so make sure you check with the manufacturer about compatibilty. i do know the new digital ignitions will not work with stock coils. tried it with the holley prostrip annililator system and an msd coil on a '92 tbi. would not start. called holley and that is why. need a digital compatible coil.

So if you buy a CD box with the right coil, is it okay to use it on street cars?

talk with the manufacturer they will tell you the right one. i personally use the holley prostrip annililator ignition with the laser shot pro coil.