Help me pick a distributor!

[funknut]

I have a 440 currently running an MSD Pro Billet distributor with MSD-AL2. It has a pretty big cam (Comp XE285-HL; 241/247 @ 0.050, 0.545 lift). Manifold vacuum tops out around 12.5" at 40 deg advance at idle.

Over the summer I was having some issues with running too rich at idle. Some great folks here helped me figure out that more timing at idle would be good. Thread for reference if anyone's curious:

Looking for suggestions. Uneven spark plug coloring. Some are super dark, some look good?

The MSD only seems to be able to get to 12 deg of vacuum advance, and I would like to get around 40 degrees at idle, so I figure I need around 25 deg of VA. I was looking at the following options:

Chrysler 413-440 “RB” Low Deck 426 Hemi Ready to Run Distributor w/Vacuum Advance FC-1007B - Chrysler 413-440 “RB” Low Deck 426 Hemi Ready to Run Distributor w/Vacuum Advance FC-1007B

or possibly:

Chrysler 413/440 V8 Distributor

The progression unit is quite spendy, but seems very customizable.

The firecore is on backorder, I'm waiting to hear from Mancini if they have any on the shelf.

Do you think I can get there with a traditional VA canister? I was reading this thread over at FABO and I can't quite tell if I'll be able to get to 25 deg of VA with the 'normal' vacuum can.

How To Limit and Adjust Chrysler Vacuum Advance Cans

Any other options I should consider? It's a street car, so cruise manners are a top priority.

 

[snakeoil24]

Did you say 40 degrees of vacuum advance at idle?

 

[funknut]

40 degrees of total advance (base+vacuum) at idle. I'm currently running 20 base with 12 from the MSD vacuum advance. Ideally I'd like to get back to 15 deg base with 25 vacuum for 40 total.

When I adjusted advance with a vacuum gauge, I was getting 12.5" max around 37-42 degrees.

 

[Geoff 2]

Funk,
Not surprised that combo needs 40* at idle. You 'get' it. Sounds like post #2 doesn't...& there are plenty like him.....

[1] You will need a dist with adjustable VA unit.
[2] The best ones are the HEI style with the long body, these have the best adj VA units; however they may not fit all alum heads.
[3] The VA in these units have about 30* of VA available.
[4] You can use this dist as a stand alone & get rid of the MSD box; or use the p/up in the dist to trigger the box.

 

[Geoff 2]

For Snake oil & others....

 

[diesel_lv]

I'm a big fan of the Progression distributor. I can run a high idle advance n have it pull back or advance as I need.

 

[HALIFAXHOPS]

Mopar Vac advance are only rate adjustable not to add or delete timing. Just FYI Adds are misleading and dont tell you that just that they are adjustable. I wish someone made one that is.

 

[69XMan]

I run a progression distributor along with a MSD 6AL. I bRice it would do everything you are looking for. Very easy to install and work with. You don’t need the MSD box but I already had one installed.

 

[biomedtechguy]

I have the latest Progression Ignition that adds a 2 step rev limiter and N²O timing retard. It's going to have to wait for my 572 stroker and a car to put it in, but I've been a fan of the Progression for years!
I just saw this and emailed Ted at Progression about it, and hope to get a reply with comparisons or comments.
MSD 6423 MSD Ultra 6AL Ignition Control - Red

 

[biomedtechguy]

Here's some screen shots of the latest Progression control app:

 

[snakeoil24]

Funk,
Not surprised that combo needs 40* at idle. You 'get' it. Sounds like post #2 doesn't...& there are plenty like him.....

[1] You will need a dist with adjustable VA unit.
[2] The best ones are the HEI style with the long body, these have the best adj VA units; however they may not fit all alum heads.
[3] The VA in these units have about 30* of VA available.
[4] You can use this dist as a stand alone & get rid of the MSD box; or use the p/up in the dist to trigger the box.

Geoff please. Help me understand 40 degrees at idle so I understand

 

[biomedtechguy]

I had lots of problems with my 440 6bbl at idle until I installed the FBO ignition system and Don set it up so I could run about 20 degrees of advance at idle but not exceed 38 degrees all in, with vacuum advance taking it higher still.
I believe I had 20° of advance plus 12° vacuum advance at idle, so that would have been 32° total advance at idle and the "petroleum refinery" smells were gone and it ran great.

 

[Krooser]

Lock out your dist at full advance and install an on/off switch so you can crank the engine then turn on the ignition.

 

[snakeoil24]

For Snake oil & others....

View attachment 1602780

I wish you could save as attachment I really would like to read

 

[funknut]

"Idle Speed Ignition Advance

The more vacuum an engine pulls at idle, the more rarefied the charge is as the piston approaches TDC on the firing stroke. The lower the cylinder compression pressure at the time of ignition, the slower the charge burns. This calls for more advance, so that the cylinder pressure still peaks around 15 degrees after TDC. Advance becomes less sensitive after about 35 degrees. To get an optimum idle for the least amount of fuel consumption, timing often needs to be as much as 45 to 50 degrees before TDC.

As soon as the engine RPM comes off idle and even a small load is put on the engine, the timing needs to drop back considerably. Building a conventional mechanical distributor to give the right advance characteristics is difficult, but if the budget covers it, many programmable electronic ignition systems can accommodate an engine's true requirements at idle and in the low-load, low RPM mode. Once above about 1,500 RPM, giving the engine what it wants in the way of timing is a straightforward job, whether it's a mechanical or electronic programmable system."

 

[Geoff 2]

Snake,
Does the above answer your question? I have tried different DPI settings on my printer to try & make these articles more legible, but doesn't seem to help.

This may also help, might have to type in manually. Scroll down to post #6.

www.hotrodders.com/forum/vacuum-advance-hooked-up-directly-manifold-bad-47495.html

 

[65Fury440]

I'm a big fan of the Progression Ignition unit as well.
I used to think I could set up a curve just fine. This system is such an easily tunable unit, I'll never go back.

 

[XCELLR8]

To those of you running the Progression Ignition unit. Did you have to trim the head, if so, how much. Can a die grinder do it or is it a machine shop trim?

Edit: I'm running a 400 B-block if it makes any difference.

 

[Charged440]

I didn't have to, 440 with iron heads and MT aluminum valve covers. The ability to lock out the ignition with the app is a nice plus.

 

[diesel_lv]

To those of you running the Progression Ignition unit. Did you have to trim the head, if so, how much. Can a die grinder do it or is it a machine shop trim?

Edit: I'm running a 400 B-block if it makes any difference.

I've got Stealth heads on 383, no head clearance problems. My large aluminum valve covers needed to be dimpled a little, but I do believe he has changed the cap to resolve that issue.