MSD, HEI, or OEM?

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T56MaxTorq

T56MaxTorq

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Been wanting to upgrade the ignition on the duster. Right now it has a Mopar chrome box with a 2 ballast setup. Wanting a 12v to the coil setup, probably a larger plug gap. I have a 12v coil already and an MSD box. I've used the MSD 6A before a few years back but now the box seems fried. Doesn't fire over and no 12v to the coil.

Motor specs are la360, touched up x heads, ld340 intake, 11:1, headers and duals, MP .528 241/241 solid flat w/ MP roller rockers I think they're aluminum. 600 cfm edelbrock @ 6500' elevation. Timing is set at 19 initial, 34 total, dist recurved for mech weights only. No vacuum advance.

I've ran HEI in a truck and liked it, it was rather cheap. I think $25 for the control unit and an extra fits nice in a glove box.

Mainly hoping for a better idle by adding spark energy at idle. Runs choppy, 10-11 inches vacuum at 1000 rpm and 5-6 inches at a steady 800 rom curb idle.

What are you guys running?
 
I recently changed from an HEI 12 volt module to a Crane 6.

Probably self-evident, but my engine now idles more smoothly, has an average operating temp of 10 deg slower, and most obviously has shown an improvement in gas mileage.

10.5:1, Comp XS242S cam, DC Tach drive dist, Bosch HEI coil. 98 Premium.
 
Back when GM first went to HEI I notcied they were setting the spark gap at .06 or more. I also noticed they got better fuel milage than others, even at NASCAR. Fast forward to todays production vehicles and you'll find every mfgr has followed suit.
It's my belief that as the quality of pump gas continues to go down we will all be looking for a hotter spark for our older vehicles
 
Just did some rewiring of the 67, a mild 360, "the interim engine." Decided to try an HEI. Easy peasy. Running stock coil, for now, screwed it right to the firewall to the left and under the wiper, no ballast. REALLY has a hot spark, cranking. No tach problems.
 
Threw on the hei I had on a ramcharger in work and it ran terrible..no idea what I did wrong but the msd box and hei don't run right. Back to the chrome box for now lol
 
When I first got my car running I was using a Mopar chrome box with a MSD blaster coil, but for a birthday gift, a good friend gave me a MSD Streetfire box. I liked the fact it has a rev limiter, but I really didn't think it would make a significant change in the way my engine runs. Boy was I wrong, it was such a big difference I swapped back to the chrome box to make sure I wasn't imagining things (I made it to where the chrome box could be swapped back quickly if the MSD failed). I can't say whether or not it was a huge hp/tq increase, but it's soooo much smoother now. I now know why they're so popular. Good stuff.
 
Awesome! Thanks for the input. If I didn't flatten my cam yesterday I'd totally buy one. The MSD 6A I have is defiantly an old model and came off a ford that had a small engine fire. I hauled it around the world and it has been in extreame temps, -40 - 105 if not hotter, and has probably has gotten wet more than once. I put it on my ramcharger and it worked, but that was years ago and I swapped to HEI instead. It was worth a shot trying it but I'll just go buy a new or used one. I think 12V to the coil is necessary and as good of an ignition system a chrome box is, it's obsolete. Maybe this winter..
 
Well that sucks about your cam (not like I'm telling you anything you don't already know). Sorry to hear about that as I'm sure it's very disheartening.
 
The Davis Unified HEI distributor is one kickass solid unit. Get a set of their wires along with it. Just as good. Awesome setup, and when you consider the fact it's a complete fully self contained ignition it's also cheaper than an MSD rig...and it's just as good.

All you need is to hook up one wire....chuck that stupid ballast resistor, clean up the firewall without all that harness everywhere...it's win.

Usually when you get it, it requires no tweaking either since they custom curve it based on your specs...set your initial and away you go.
 
Better yet just use lock out timing and run a 3,000 or more stall and loose gears. Motor will idle the best with 35 degree timing. I'm using msd E-curve dist and the lock out timing curve set up.Have a msd 7 al box and matching hvc coil to fire the plugs.

Yes these carb engines need a hotter spark since the fuel is for F.I. mist now.

Why running stock isn't so hot, if you had 1975 fuel ok, if not get the hottest spark you can afford keeping in mind the wires have to handle the spark. Sleeves might be needed over the spark wires to help cut down on crossfire and shorting to ground.

If you just slap a msd 8 box and hvc coil on most any wires 5 years old or more, LOL

The 5 and 7 wires need to be as far apart as poss
 
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