Well ive had all i can take with my Mallory setup. In the past 2 yeas ive had 2 distributer LED's go bad, and a Hyfire IV box go bad. Now my tach is getting oddball signals at idle....Its time to make a switch this winter. SOOOOO i was wondering if i should go the MSD digital 6 route or step up to a digital 7. Im never going to get serious on bracket racing. Its more of a street monster, that will see a good share of track time. My question is....is the Digital 7 worth the extra money or am i better off with just a digital 6??? Who runs a digital 7 on here? I know the Digital 6 is a great ignition first hand and im leaning twards that but if the Digital 7 is a BIG advantage then i guess why not spend the money....what do you guys think? Also how hard are the D7's to get tuned?

Well,

don't take this the wrong way, I don't know your situation...but...Why?

your best bet if you want reliability is a GM HEI. those boxes do nothing for performance. unless you have deep pockets and need to spend some money, why not put the $ where you could gain some real performance or a safety improvement?

Well ....i have a 73 Nova and for 1 an HEI dosent fit the fire wall....tried that. And for 2 they may not necessarily make more power {wich im under the assumtion they do otherwise i dont think anyone would use them} but im running sort of high compression on pump gas, i need the 2 stage rev limiter because i run a 5 speed and the top end retard sounds like a neat feature. Also it would help my "big ass" cam idle a hair better and possibly more consistantly, start easier and give me better gas mileage...ive seen the effects of a digital 6 on my kind of motor and it is in a word, amazing, compared to an analog box. Im just wondering if the Digital 7 would be a better route or should i stay simple and go digital 6.

I have an opinion. If you are running on the street, you are traction limited, no question. Soooo, with one of these new fancy-ass boxes that can map a retard curve every 100 rpm, {or less?}, you can play with it until you dead hook, and negate the need for tubbing, street slicks, etc. No use having power on the street unless you can hook it, unless you just want to show off, like I did last night in town.

Go with the programmable digital 7.........Summit has them on sale for $170.00 off. Just picked mine up today..........heck if you don't use it you can return it or possibly even sell it for more in 6 months..........

just curious, what is your combination, ET, cam, compression?

As with many other Novas, I know it stinks that you can't fit the HEI in there without beating on the firewall. If you feel you need the 2 step and would like some better idle quality than the Digital 7 over the 6 why not. I agree the high speed retard is also a good function. After 3000 RPM (or close to that) there is no more multi-spark and just because everyone buys them doesn't mean the work for every situation...I can list 10 more parts where this ripple effect has happened.

High cylinder pressure motors including nitrous and blown motors can benefit (maybe performance wise.) Unless the cylinder pressure is slowing down the flame front so much like can happen with one of the high cylinder pressure situations I will hold steady on my statement that you will not see a decrease in ET with any CD box when compared to a properly operating ignition system including the old points setup.

The extra's like the 2 step, start retard, some idle quality, high speed retard, laptop programable timing curve are all excellent extras to help a bracket racer fine tune the combination for consistency, but your original post complained of ignition problems and you are not going to be ever bracket racing, so why the expense? Your car will run the same ET with or without the Digital 7 box if you take the time to tune it and discover a launch technique

This discussion is not necessarily aimed at you since your mind has/is already made up.

This is really for others who may be comtemplating the same decision and should be putting their $$ where it will help them with their ET goals.

Okay, you are space limited - but that does not mean that you too cannot enjoy the relibility of an HEI. Just go to http://www.davessmallbodyheis.com/
and there is your answer. The small body HEI retains your small distributor cap size by putting the module outside the guts of the distributor.

There is a lot that can be said for today's technology and the amazing MSD digital programmable 7 & 7+ (7530 & 7531) - but even when dinosours roamed the highways the comparatively weak points or transistorized ignitions still fired away on some amazingly fast cars. An HEI has far more firepower than any old points or old magneto ignition, meanwhile giving you on the road relibility that the old dinosours never enjoyed when new. HEI's are "inductive" in spark generation, which almost always gives them superior start up and low speed operation. They still fire fine at the top end - I have used them on engines into the 700hp range.

Thomas

Well i just priced a D7 and to my surprise it was over 200 more than i thought, so im going to forgetabout the 7 and go with the 6, thanks for your imput guys.

Originally posted by Nickel333:
Well i just priced a D7 and to my surprise it was over 200 more than i thought, so im going to forgetabout the 7 and go with the 6, thanks for your imput guys. I just bought a Digital 7 programmable from Summit today for $499.

One of the mags did a dyno test while back with points, hei etc. and power numbers were for the most part dead even. Less than 2hp difference. The lesson from the story is as long as the spark is adequate to fire the mixture the power will be the same. I have also been looking at the digital 6 for the features it has it looks like the right system for my application. Five years ago I put basic MSD6 unit with blaster coil in my Dad's 85 dodge pickup with good results-the engine ran much smoother and he actually picked up 4 mpg. The stock mopar system must have been junk.

Okay, I only want people to think about the following because I've seen post/reply like this before.

Post: which ignition to use?
Reply: I replaced a dead factory system with a brand new abc system and the engine ran smoother and mileage went up 4 mpg.

What I want to know is: why do so many people associate miracles with one aftermarket ignition or another? Is it not true that ANY new ignition would have helped when the original was dead? On another note related to emissions compliant cars: some non emmissions compliant ignition systems allow tuning that increases fuel mileage and performance, but puts the car out of emissions compliance. As already pointed out, when several systems were tested only a couple of hp separated the top from the bottom when the tuning was the same. Unless one had a stinko curve, there is no way that a couple of xtra hp will give you a 4 mpg increase.

Thomas