Do I need to add a ballast resistor when using an MSD coil with my tbolt IV ignition. The coil info says to add it if using a "stock points" style ignition. I'm not sure if that includes the tbolt IV or not.

Mike

I have a IV with MSD (for the blower) and I don't use it.

No, you don't need a ballast resistor. Your Merc ignition is HEI. Which means it dosn't have points. I don't know why you would want to use MSD? You would be better off with a V-6 moduel. MSD is very over rated.

T gary , what does the v6 module do? I think he was just replacing the coil , the merc one runs 18,000 volts and the msd one 40,000. I did the same thing to mine. sh

A V-6 moduel only has 14 deg of advance. So if you set your total timing at 32, you have 18 initial. It will start just fine, and You will notice better throttle response. Chevys seem to like more initial timing.

Do you have a part # and a ruff cost? thanks sj

I have a TBolt IV with a blaster cpil and the MSD 6AL with rev limiter built in. Setup runs fine. Good idle, no transome soot. Can't tell anymore power but certinaly runs smooth.

Thanks for the responses. That's what I thought, but I wanted to hear it from the experts.

Stevejohns, The moduels come in two different styles. One bolts to the exhaust riser, the other one piggybacks to the distributor. I would need to know which one you want befor I can get you a part #.

TG.. mine is the one that sits against the riser. Thanks sj