Coil wiring questions

As many of you know I've got 2 msd blaster ss coils on my '84 ca18. They've been on, and running fine for 2 years now.
Today I decided to go out and wire the secondary coil to fire all the time....but before I even started doing that I decided to check the volts where the pos/neg wires hook up to the coils at.
Well......to my surprise when I checked the volts with the car running, I got like -15 volts on each coil?? Shouldn't I get a pos. number instead of a negative? I checked the wiring going from the transistors to each coil, and on the transistors there is a blue wire and a black/white wire. To my knowledge the blue wire is positive.....and I have the blue wire from each transistor running to the pos terminal on each coil, and the black/white going to the negative. Now it's been wired like this for 2 years and runs fine.
I reversed the wires at the coil terminals, and checked the volts, and got a positive number......and the car also ran perfectly fine with them this way too.
So does anyone know if the blue wire is the positive, and should I get a neg number with the volt meter at the coils??
Shouldn't the engine run bad or not at all wired one of the ways?

Although you should get a positive number it doesn't matter which way you hook it up. The coils don't care if you hook them up backwards they'll work the same way.

Really? So I guess the black/white wire leading from the transistors was the positive, instead of the blue wires?

Mine's wired up the same way. And it runs fine I used male connectors to plug into the connetors from the power transistors. I also thought that the black/white wire was ground.

My install isn't very clean though i have household elec. boxes as brackets

Yeah.....I've got the male connectors plugged into the plugs leading from the transistors too. I didn't want to cut off those plugs just incase I ever wanted to revert back to the oe coils.
Ok....so should I switch it around so the the black wire goes to the pos terminal, and the blue wire going to the neg terminal.....or it just doesn't really matter?? I know when I take the plug boot off the coils, I get a nice blue spark shooting from the coil to the strut tower.
Also......any idea what volts I should get at the coil terminals at idle?

Hey Johnny don't sell yourself short I thought your electrical box coil mounts were pretty clever. I like how they sit at different angles so the coil wires can run straight out of them.

yea they certainly are available :razz: . I didn't even think about the angles of them. They work and that's good enough for me.

Did you finish the mod? If so can you give us the opinion about using MSD Blaster SS coils in "twin" mode?