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I have finally got my car running well, so I'm looking for the next upgrade. I currently have a GP Sorenson box (used to fire the dizzy on my '289 when I bought the car) firing the stock '89 351W dizzy. Will switching to a MSD box (or similar aftermarket performance box) help make more power? I'm debating on wether to upgrade the box or go for some roller rockers to replace the stock non-rollers on my 351W (I can helpfully reuse the roller rockers in a year or two when I buy aluminum heads). $ vs HP, which way would make the most sense? The MDS and other performance boxes talk about how many times they fire per cycle etc etc which they lead you to believe helps make more HP vs a factory setup. The GP Sorenson, I believe, is a stock type replacement. Thanks /forums/images/icons/smile.gif

Shane
 
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The roller rockers really make the most sense dollar wise. The MSD will gove you a nominal amount of power but what it will do & do well is burn fuel more efficiently & help take away some detonation. I'd go with th 6AL & retain the Durespark distributor.
 

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Well Shane, the roller rockers are one of those subtle nuances that don't show up in the "seat of the pants" dyno. The main deal on roller rockers is longevity. By using a roller tip, it reduces friction and helps with the angle on the valve tip. Maybe you could pick up 2 or 4 hp by these. Crane or Comp Cams could tell you via their toll free tech line. On the other hand, the multiple spark boxes, combined with a hotter coil, can increase both performance and gas mileage. This is because with the hotter spark and multiple discharges per firing stroke, you have a more complete burn of the fuel mixture. It tends also to smooth out your idle. I have a Jacobs pro-street system, including coil, computer, and accessory pak. There is a tuning circuit on the computer which in essence turns it off so that you can run a timing light. When I activated that circuit, there was a noticeable degradation in idle quality and how easy it was(not) to start the car. Jacobs gaurantees a 1.5% increase in gas mileage with their system.

What I also like about the Jacobs system is the anti-theft switch. this is a hidden microswitch which, if not activated within 8 seconds of starting the car, sarts shutting off your engine 1 cyliner at a time. If it shuts down the engine, the ignitiion is disabled for 20 minutes. It also has a programable rev limiter that you can reset from within the car.

ON the other hand, the jabos system was very difficult to install. I have an MSD distributor and it did not like that at all. There was no clear instructions and even the tech line was not overly helpful. I had to use a 9 volt battery as a source to send one "spark" through the system to locate which wire to hook up to the MSD "hot" dist. wire. Also, the Jacobs system will not allow the factory tach to work. I tried all kinds of settings per the instructions, and nothing worked. The answer turned out to be that I had to re-install the stock coil and use it as a tach trigger. Still use the jacobs coil for ignition, but have the stock coil for the factory tach. Very awkward.

I think MSD has an easier system for dealing with the factory tach. Also, the MSD boxes are compatible with the MSD dist. The downside of MSD, if there is one, is that it always sends the multiple sparks and high voltage to the cylinder, whether it needs it or not. The Jacobs uses the spark plug as a sensor and only sends more sparks as needed, and ramps up the voltage as needed.

Crane has their fireball system and I even read about another system that is Military spec'd from some obscure supplier that makes these ignition systems for the military. Very insulated against dust, vibration, heat. Forget the name.

If I had the money for a new ignition system, I would install that instead of the roller rockers. Just my 2 cents. Oh yes, I Have Crane gold roller rockers too. I read not that Steeda has roller rockers which are semi-shat instead of pedestal mount. They pair two rockers on a short shaft. Don't need guideplates. The steeda rockers are 1.7ratio compared to standard 1.6 ford small block, so you get more lift out of your cam.
 

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I have Performance Distributors D.U.I. I really like the one-wire set-up. Very easy.
But if your ignition is working, another this or that box will not make a notable difference under 6000rpm. I would save and purchase the alloy heads 3-6 months earlier.
 
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