David it will retard from both, from the 40* when below 3k and from 35* when above 3k. Yes run curve is "active" in and out of boost. Run curve is rpm dependent, boost curve is vacuum and boost dependent, "above and below atmospheric 14.7". So both add together run+boost= total timing retarded.

 

Thank you very much! That makes sense, then it's more like a 3D map. The way it was i only had 20 degrees at full boost. Made a new table today with 24 degrees and locked the distributor at 40 so that I can ad a bit more during cruising.
It's a Sbc 305 and running 11 psi at the moment. Made 294 whp but hoping for more.

/David

 

Just remember what ever you set locked dist. at will be your max timing period. If you want 45* at cruise or above 5500 you must set locked dist. at this number.
You can always take it out with your run curve where you don't want it and add it back in where you do.

 

Subscribing ...

 

Not much action since last year

 

I see that. I will most likely be getting a 6530 box in the spring and I want to find this thread, lol

 

a lot of good information in here

 

I actually went with this ignition box after reading this thread. Love it. Simple enough for me to understand how to use it, but still has a bunch of useful features as well. I wanted one ignition box that would do it all instead of buying a bunch of add-ons to a regular 6AL box

 

So stupid question time. I plan on buying one of these for my BT carb build. When I see everyone talking about locking down the distributor....are we talking in a sense of setting the timing only at max degrees used, or are we also talking about locking down the distributor by disabling the mechanical and vacuum advance? Just not sure if a street car should keep the vacuum advance going as always recommended (I know thats NA thinking). Though I guess this box replaces that need if you can tune it?

 

You lock it out completely... fixed timing regardless of rpm, or vacuum. The 6530 with a map sensor controls the curve. Lock it at your max timing, and the MSD pulls timing to match your curve (within reason).

 

Thank you for clearing that up Mnlx

 

No problem.

 

Im running EFI now and still have my timing at 37 everywhere out of boost ....... everywhere

 

Yeah if I would have gone 5.0, I probably would have went the EFI route. Too bad GT40 intakes for the 351 are silly on pricing now. I saw you went to the dark side Blown, as it looked like you are very experienced with the carb setups like Mnlx is. Trying to do a budget build...even though I just saw the video of Eric The Car Guy and his detonated piston with his turbo carb. My build I found is similar to his without the nicer heads and cam. I appreciate everyone’s help on this site as it’s very informative. It didn’t even click on the ignition system requirements....until I got deeper into builds.

 

I know just enough to make them kinda run. Guys like 385 know much more than I probably ever will about blow thru carbs.

 

That may be true(?), but your knowledge has really helped me out Mnlx. Once I finally get everything in I am sure I will have lots more questions. So hopefully all the carb gurus don’t get amnesia between now and then. Lol