Help with Distributior Install

[Ned]

Installing a DUI distributor on a SB Chevy/Mercruiser. How can I connect The shift cutout switch?
Thanks,
Ned

[Kevin Heine]

Ned,
What kind of distributor are you changing from. I have an HEI I was going to put in mine but was talked out of it. It has been a while since I studied this but I was planning on connecting the cout out switch to the 12v going to the dist. All the cut out switch does is momentarily ground out the ignition so you can take it out of gear. REMEMBER, I never did it. But, I don't see why it wouldn't work. I talked to a man at MSD and he told me to get a filter, he even gave me the part #, to intall befor the distributor to protect the coil.

[SoggyJet]

I am assuming that the DUI distributor is the aftermarket version of the GM HEI distributor. I ran an HEI in my Mercruiser for a number of years until I got ahold of a Merc Thunderbolt IV.
On the HEI I hooked the cut out switch to the tach terminal and worked perfect. (this way works because it keeps the coil in the circuit just like the Merc system)
Do not hook the cut out switch to the positive as that would create a direct short to ground, causing melted wires, blown fuses or even fire.
Doug

[Ned]

What they had me do is to tap into the brown wire that goes from the module in the dist to the coil in the cap. It seems to work. I tested it many times on the hose B4 I actually put it to use. Unfortunately after an exteneded full throttle run I seem to have blown head gasket or worse. Low compression on 6 and none on 4.
Thanks for the replys.

[celeb1]

Once you get the motor sorted out you can try what I did. I bought a new style shift interupt switch and replaced the switch mechanism with a brake light switch from an old chevy. They chevy break light switch fit in perfect with a hose clamp like you would bolt to your firewall to route wires and I did an inline hook up to the positive lead. This causes a momentary break of the circuit, works as good as stock. This way you are only breaking the circuit like a really quick flip of a switch and you are not sending ground to the distributor. DO NOT send ground to the distributor, I tried it and it worked for about a half a season until I burned up the coil.