Maybe You Should read the first post and then you would under stand what he is asking that is why I gave a link on a good Marine Distributor close to what he was looking at and not HIJACK his thread.

The cam in my 524 is a .623/.612 lift with a 242/252 @ .050" duration and a 112 LSA, I am running NA at 10:1. This is a carbureted motor so no IAC to help keep the idle up when Several comments have been made on the stator rusting in the MSD distributor. I soaked mine in rust remover and then soaked it in Gun Blue with a coat of Amsoil metal protector, It's been 4 years and it still looks the same as when I first did it.

The DUI isn't an option with a 1071 blower with HEI cap.

Also, I do not believe the DUI has a programmable advance curve via a laptop or pc. It uses centrifugal weights like a standard MSD distributor which the OP already has.

I have no experience with a DUI, and I am sure its a good distributor setup for the money. I still would prefer a digital capacitive discharge style ignition for a 850-900hp supercharged engine.

i prefer a mag for blower engines....

maybe you should read all the posts in this thread,you just might learn something,like i said DUI dist is not a good option for a supercharged engine and how in your mind is my post [hyjacking]the thread?

why a mag for a low boost pump gas engine?

DUI, and MSD also make small cap HEI distributors that work very well. The stock small cap GM units and coils have no problem on an 1100hp blower motor if everything else is set up correctly. There are different modules, which are easy to swap, with only two screws holding them down, and most have a very short electronic curve. Some have 4 or 5 degrees advance, some have 0. The module is less susceptible to RFI, and creates a very clean square wave signal which is great with EFI, or with any ignition box you want to use. Obviously, a crank trigger is better still, but everything has it's place.
Locked out timing on low compression blower motors works quite well if you don't have the ability to program a curve. Some of the higher end boxes will give you quite a bit of control, which for guy's like Mike, or Mild, who really like to dial their stuff in, can be an excellent tuning tool, and add some safety. You're basically running an engine management system without the fuel control portion. What you want is a 3d map that will allow timing vs load and rpm. As well, you want modifiers that will adjust timing vs inlet/manifold air temp, and knock. With these parameters you can really optimize your tune.
Running very low ignition timing at idle is an excellent way to combat reversion. Additionally, adding a bunch of timing in the high load lower rpm area where it goes into gear, can really help prevent stalling. You can add timing at low load cruise rpm to reduce EGT's and improve efficiency, and then pull it out at higher load, pull a bit near peak torque, and add a couple again at higher rpm. Etc.. You get the idea. There's many ways to do it, and sometimes the simple way is best. It's really up to the end user and his comfort level in tuning, and budget.

Alex, in regards to OP's engines. 540's, 10-71's, iron heads, no intercoolers, carbed. They are in a old 38 Cig. He likes to cruise with the family. Timing was currently locked at 32. Engines idle great, and once the carbs were dialed in, they ran good. My concern I brought up to him, is that I noticed while being a passenger, in choppy water with the drives tucked and tabs draggin a bit, at 3000-3500 he is in the boost. 1-3psi. And now he finally has some props that hook up, and load the engines quite well planing. His engines were tough to crank, even though I believe that is a boat wiring issue, as I have the same starters as him, locked timing, and a higher cranking psi on my engines.

My initial thoughts were to remove a little lead down low in the rpm band, and just bring it in later. Then I started looking at some of the capabilities of the newer ignition stuff, as far as programmability, and they have a lot to offer. While I too run locked timing, with good results, I am always open to an idea that their might be something better on the market. The 3D map is neat stuff

We are installing air temp gauges to monitor intake temps

Maybe you should read post #27 you might learn more sense you think you know every thing The right DUI will work just fine.

I love winter :food-smiley-007: