A few quick questions for you MSD experts:

1. Does the MSD 8572 tach drive distributor fit underneath small-block ignition shielding with MSD 90 degree distributor boot plug wires installed?

2. The ballast resistor is completely bypassed when using a 6AL box, correct? After reading the directions, I believe this is correct. Just confirming. If so, I can supply switched 12 volts to the red 6AL box lead with the original pink wire that runs from the ignition switch to the ballast resistor.

3. BLK and ORG leads from the 6AL box go to the coil. Directions say these are the only leads connected to the coil. Do I abandon the pink wire from the original harness that connected the ballast resistor to the coil + terminal? After staring at the schematic for awhile, I believe this is correct.

4. The R terminal on the starter originally connected to the coil + terminal, also a pink wire. If the answer to question 3 is yes, does this wire get abandoned as well?

 

1. NO. I will fit with a MSD stock look a like cap turned 180 degress.
2. Yes
3. Yes
4. Yes

 

Here's a picture of the cap you need. It fit under my shield on my L79 engine.

 

I can't help you on number #1 but #2,#3 and #4 are all yes.

 

Thank you, guys! I found the cap on Summit's site. P/N 8437. Do you happen to recall what plug wires you used? They say not to use solid core wires with the MSD. I'm not sure what type of wires came on my car, so I'd like to replace them.

 

I used stock AC Delco wires. Local parts store.

 

I really like the MSD cut to fit wires in the 8.5 mm version. They seem to hold up better than the alternative Taylor wires. Just make sure you buy or borrow the tool to make the connections. Dave

JEGS P/N 012131233 $90.99 wires
012135051 $65.99 crimping tool

 

I like the MSD "Heli-Core" spiral-wound wires; buy the "universal" set, and cut them to length after routing/clipping them. The stripping/crimping tool comes in the box with the wires.

 

Just realized that I forgot the link.

http://www.jegs.com/webapp/wcs/store...10002_81280_-1

So John what is the difference between the ones you recommend and te ones that I've used in the past? I'm always looking for a better mouse trap so I'm all ears. Thank you.

 

That's what I have. Tonight I looked up inside the distributor shield with a mirror (no wires) and it looks like there's enough room for the MSD wires. I routed the four front ones through the lower shielding (lots of fun, as some of you know). In the morning, I'll route and terminate the other four and give the upper shielding a test fit. Thanks for all the suggestions.

 

be careful when you bypass the ballast resistor. I did that on my car and when the shop was troubleshooting my turn signal switch they left the ing switch on and it burnt up the coil and fried the ing wire all the way back to the switch. DON'T LEAVE THE ING. SWITCH ON WHEN YOU BYPASS THE BALLAST RESISTOR

 

The Taylor wires are junk.

 

I think that I may have misread your original post. I have put the 90 degree MSD plugs on numerous midyears with no problems fitting the top sheilding on. I don't think you'll have any problems. Dave

 

I don't know, but I've used the Heli-Core wires on many project cars, and have never had a problem with them.

 

Do you need the adapter to get the tach to work properly with the 8572?

 

No, I have the one that came with the distributor, thanks.

By the way, I managed to get it all to fit underneath the shielding.

 

Okay... the real question was... "Did you have to use the adapter to get the tach to work properly?"

 

Oh, sorry. I misunderstood your question. I read another thread on the forum that says the adapter is required. After looking at the cable and drive on the distributor, I believe it. I'm a few weeks from getting my gauges back and installing my dash harness, so I haven't hooked up the tach yet.

 

No worries... would love to hear how the tach works and whether you need the adapter or not to get proper rpm...

Thanks