Is vacuum advance needed with MSD box with a daily driver?
Just an FYI
In my 11.3Scr 367/ A833, 68 S-clone;
I ran the 292/292/108 for two years on an Orange box, and an Accell sq-top SuperCoil. It spun to over 7200 with that set up. And made power up there too.
but the bottom was real soft with 3.55s, so I swapped them out for 3.91s. And then 4.30s and then 4.88s,and then 5.38s.
Along the way I moved the cam 3 times, and noticed as good as no difference, I even retarded it just to see what would happen.
Along the way I also bought a GVOD, cuz 5.38s are insane.
I got rid of that nasty-boy cam.
I then got me a 270/280/110 hi-lift, went back to the 3.55s and installed a 3.09 low gear set.
I then got me a Jacob's CDI Ignition with an E-core coil. Which worked for a couple of weeks and puked, so back to the Orange box. Then I installed the Jacobs dial back Timing device.Then the Jacobs CDI came back from Warranty, so I bolted that back on. Which lasted another 2 weeks or so, and puked again.
BTW I noticed absolutely no difference between the CDI/E-core and the Orange box/Super coil.
Then I discovered that the DB device had an amp in it, so i hooked that up, beside my Orange. I wasn't gonna pay for another tow-call! After about a year of no problems, I finally pulled the Mopar stuff out.
Now, I gotta tell you, a streeter IMO has to have a working Vcan. When you cruise that beast with the 288 cam, she will want between 50 and 60 degrees of cruise timing. Why? cuz if you don't give her what she wants, see post #26. You have got to start the fire really early, so all the fuel has time to burn. I run really lean on cruize, and that means the fuel in there has a hard time finding oxygen to react with. So by starting the fire early, I hope it will all have reacted by the time the exhaust valve opens. With a 288 cam, the power stroke is very short in terms of degrees, so there will still be a lot of energy left when the exhaust valve opens. This is of course wasted energy now, and there is no cure for that except a smaller cam. So you need to make the best of that, by starting the fire early.
But 50 to 60 degrees,obviously is not possible without a working vacuum advance system.
And there is a little thing called Part Throttle. Cruising around at 2500ish, again the timing will want to be in the mid to high 40s or even early 50s for the very same reasons earlier talked about, but now, also to tame that beast. By giving the engine the advance she craves,She will run a lot smoother, and you can lean it out some more.
I will never run a big cam again.I would rather put the power in the heads.
I run a 276/286/110 now, and that is the limit for me. When it dies, I will be downsizing again.And I will be upping the Dcr some more.
Gears are my friend. Extended rev-ability is my friend.