I'm having my stock 302 built up now by an experienced shop in Dallas (Lone Star Performance). Stock block, AFR 165 heads, Edelbrock RPM II and Anderson N41 cam and all the rest. They are adding new fuel pump, adjustable regulatory and 30# injectors as well.
The shop is telling I really don't need an EMS. They said that they know how to adjust the timing and fuel pressure to get extract the performance out of this setup.
They have a dyno tuner but don't have the software / systems to do the older cars.
If they get 325 to the wheels, I'm going to call it a win.
What are your thoughts?
Do you NEED an EMS? -- No
Could you benefit from an EMS -- Yes!
You could run the old A9L ECU with a calibrated mass air meter, and it would run reasonably well. The down side will be that you will have some small drivability problems, cold start surging, etc. There is no way you are going to get the power you want without a tune. I don't think you would get it with a tune either with that engine combo. That parts combination will be a vast improvement, but isn't going to get you 325 at the wheels. Adjusting the timing will give you some power. Adjusting fuel pressure is one of those dumb things that people do that accomplishes nothing. The O2 sensors are just going to pull that extra fuel in closed loop anyway, unless you are going to run in open loop, which I would not recommend. A chip tune will let you advance the timing properly, and command whatever amount of fuel you want.
But now you're tied to that tuner, and you have to hope that he actually knows what he's doing, and you have to pay him over and over again each time you make a change.
My advice would be to get it over with and get an EMS, but shop wisely. Buy the wrong one, and you'll be worse off than you were when you started. The old A9L is a better choice than many of them. If there is an entire forum section dedicated to just the particular management system you're thinking about, maybe that should tell you something. Do not shop based on price. If you can't afford a good one, then don't buy one at all. Look at the experience others have had. How steep is the learning curve? If they had problems, will you have the same problems? Or did they just not follow instructions? Or did they use junk parts? If you have trouble, how good is the tech support? Will the tech people actually be able to solve your problem? What will it cost to install? The price of the system is just the beginning if you cannot install it yourself. If you're going to pay someone to install it, and it doesn't come with a custom fit harness, you're looking at a lot of labor to make a harness, or make a universal harness work. That will be costly. And if the system just uses your old harness, do you really want to rely on the old worn out original harness? Do you need to pay someone to tune it, or can you do it yourself? If you have to pay someone to tune it, well then maybe you should have just had the A9L tuned. Is that tuner any good? How do you know? That tuner will of course tell you he's God's gift to tuning. I can almost guarantee that he isn't. And the testimony of other customers that wouldn't know a good running engine if it bit them in the arse doesn't help. How good are the parts? The quality issues with aftermarket parts are no secret.
In a nutshell, yes I'd buy an EMS. But choose wisely!