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View Full Version : HEI..or a MSD Box



SicMonte
05-30-2005, 07:43 PM
ok...now im confused. I was reading the article in PHR on the progect g28's new motor...and it has an MSD HEI distributer. I know it has the module and the coil in the distributer...I have one in my car (proform).

Now for my question. If the HEI is good...then what is the MSD box...6A..6AL..whatever type...what do they do??? Can you use one of them with an HEI? Im just confused....someone explain this to me!!!

novaman_68
05-30-2005, 08:04 PM
Yes you can use a MSD 6A or 6AL either one with a HEI. The box has two wires that plug into the pickup coil (purple & green I think) bypassing the module. The advantage of a MSD (Multiple Spark Discharge) ign. box is that it produces a much hotter spark than stock and it sparks several times instead of once like a stock ign. They do help I did the install on a car with a stock HEI and you could feel the difference in the seat of your pants.

SicMonte
05-31-2005, 02:41 PM
did you use that "super HEI" kit that includes the box...coil and coil wire...or did you just use a box?

Tom Welch
05-31-2005, 07:03 PM
Check out Performance Distributors. They say that a properly setup HEI will neither need nor benefit from an ignition box. My experience with HEI's bears this out. I believe that ignition boxes work but dyno testing of several of them in a mag article I ran across a few years ago produced no useable increase in horsepower ot torque. I believe that they will help fire plugs that are used in high rpm or forced induction situations.

novaman_68
05-31-2005, 07:23 PM
No I did'nt use the super HEI kit, I just used the box.

Quote "They say that a properly setup HEI will neither need nor benefit from an ignition box. My experience with HEI's bears this out. I believe that ignition boxes work but dyno testing of several of them in a mag article I ran across a few years ago produced no useable increase in horsepower ot torque." Quote

Tom what do you mean by "properly set up" ? I put the box on a bone stock HEI and there was a very noticeable difference. As far as I know in stock form it was working fine, it pulled all the way to 7,000rpm with no problems. I just put the box on because I got it in a trade.

79TransAm
06-03-2005, 06:21 PM
from everything ive heard it gives hotter, and a cleaner burn above the usuall range of HEI(around 4500rpm) If your going budget id reccomend using the stock HEI distributor and going with a MSD 6AL box. If your willing to spend the extra couple hundred dollars id go with a msd distibutor and the HEI Super kit with the 6AL box(6AL box allows you to add "pills", what they do is stop the spark after a certain rpm so you dont over rev.) But im sure there are people on here more experinced than myself.

Tom Welch
06-04-2005, 02:49 PM
By properly set up I mean that by having the advance curve matched to your cam profile the ignition system will provide optimum performance. I tested an msd-6a box on a stock hei and then used one that was stock but the advance curve was matched to the cam. I got the same acceleration and driveability with both setups. No need for a box in my opinion. This was in a 78 T/A with a 428 pontiac engine, 4 speed trans, 3.42 gears, hydraulic cam, headers, 2.5" duals with x pipe. 13.80's both ways. Running a Qjet and stock iron intake, stock heads.

SicMonte
06-04-2005, 09:16 PM
By properly set up I mean that by having the advance curve matched to your cam profile the ignition system will provide optimum performance. I tested an msd-6a box on a stock hei and then used one that was stock but the advance curve was matched to the cam. I got the same acceleration and driveability with both setups. No need for a box in my opinion. This was in a 78 T/A with a 428 pontiac engine, 4 speed trans, 3.42 gears, hydraulic cam, headers, 2.5" duals with x pipe. 13.80's both ways. Running a Qjet and stock iron intake, stock heads.

ok then...how Do I match the advance curve with my cam?? I have the comp cam x274 cam.

Tom Welch
06-05-2005, 05:05 PM
Contact Performance Distributors or find someone local to you that can set the advance curve on the distributor that you have.