Distributor advance q’s.

I bought a new distributor for my newish motor and want it curved. My engine builder asked me how I want it curved. At that point I realized I don’t have a complete understanding of what I should do. I know cam duration and timing has an effect.
I want my car to start easy but the more I advance the easier it starts although it starts to work against itself as well. Just thought I’d ask advice here and see what I can learn.

So @ what RPM do you want your timing to be at full advance??

Never mind

So motor specs, cam specs, Torque converter specs, where is cam degreed are all nice to know. headers, intake carb and such.


Looked up your other posts and with 511 and 274 @ .050 I would put light mister gasket springs in to have it all in by 1000 or 1200. No vacuum Advance.

(1) set the initial with the "vac gauge method" then (2) buy/use the $25 FBO plate to limit the total (initial+slots) to the "std" for your eng (35-sb) which will get somewhat "close" then (3) mix/match springs so you are just under the pinging point at WOT up thru the gears on your hottest/driest(most likely to ping) day then (4) plug in the can to ported & adj it so you are just under the pinging point in everyday driving under varying RPM/load conditions & adj it (slope not the total) with the hex wrench. Peoples' hearing varies & there is "silent" ping so give it a cushion. "manifold" porting for the can is touted by many people & locked out timing has its place. Bottom line: NO pinging, you want to get "somewhat" close that line but never over it. Any combo of springs (except for the OE heavy spring with the elongated loop) advance in a linear rate so any combo of chebby or transdapt or mr gasket or MP springs are OK to get your ideal combo.

Depends on the distributor and how much time you're willing to pay for. If it is a MSD billet then there is a selection of springs and bushings. The instructions show you the different curves so you just pick it out and install it. If you have an older Mopar distributor then you're kind of up a creek if you want to dial it in. Back in the old days people would braze up the slots and file them to size and all of that jazz. If you have a modern digital distributor then you can set the curve by just turning the dials.

80% of units with MSD can start with black stop bushing and one light silver , one light blue spring and be right on The way they send them out the door they are almost unusable Also spray WD40 on the reluctor --they are some odd metal and will corrode making unbelievable mess-- stopping you in the middle of the road

FBO plate should get Mopar product of the decade--awesome problem solver backed by a smart patient guy Wish I had invented it

If it’s a race car, I’d start out with it locked.
If it doesn’t fight the starter when it’s hot...... you’re done.

If you set the advance so you have between 14 to 18 BTDC idling with 34 to 36 total above 2000 RPM it should fly

proper advance curve depends on a lot of variables, I use performance trends engine software, it will plot an advance curve for your engine, then use a distributor machine or a timing light and have a buddy hold the throttle at different rpm's and plot the results, swap springs and weights until its right. The program is relative cheap and it calculates a ton of other stuff.
http://performancetrends.com/Engine-Analyzer.htm

The distributor is a 440source. No vacuum advance.
Yes it’s 511
11.5 to 1
274@50
4800 stall
Will be 4.10 gear with 31” tire

If it were me I'd put these advance springs in and go!
https://www.summitracing.com/int/parts/mrg-925b

This is how we've been taught to do this but recently a buddy named William Baldwin has woken a few of us up to the fact that locked is not always the answer. There's a thing called "slew rate" which is the natural act of electronics retarding when you hit the gas and I've checked it on my Dart and sure enuff, the timing retards about 1 degree per 1000 rpm's.........NOT good people and I will be sending him a new MSD dizzy to "fix" for me and I will report back as to how it works......

with 274@50 - first I would dump that 440source dizzy and go with an MSD unit - but if budget demands use it but watch the internals as they have a tendency to destroy themselves after awhile. As far as a curve you will want about a 10 degree curve with all timing in by 1500 - 1800 RPM. The light weight mr gasket springs usually will get you there - if not drill the counter weights to lighten them up. another way is to lock it out and use a start retard function AKA msd starter saver or a digital 6 box

Yep and william answered one of my threads on timing curves stating all in by 5000rpm using the big factory springs with the loop. 10* curve starting at 26*@idle on my 511 with 11.25:1 comp using a 270@50 solid. He likes the factory distributors.

Does this guy have a web site or something?

Yep. Baldwin carbs.

Thanks MD

FB Baldwin Performance Carburetors.............

Was going to have him do me up a stock unit but can't stand the male ends on the caps so MSD for me unless they make a male cap for Chrysler dizzy's........

Pretty sure they do Dom. Seen them on FBO. Was thinking about getting one of Dons distributors and send it to William for curving. I will have to test fit an old unit i have first to see how well it clears head and cover.

I'll look into that then..........

Looks like summit has those caps too.

Firecore sells a "convesion" cap for the factory dizzy that has HEI Male ends. See: https://www.customwiresets.com/product.php?productid=16275&cat=0&page=1&featured
I've been running this cap and a FBO mechanical advance selector plate for several years in my factory distributor. Works GREAT!

Thankxxx guys............

Who think the most efficient spark setting for an idling engine is full advance?

It probably isn't in most cases but we've been doing it forever and I too am guilty and will be trying a curved dizzy in my junk soon.........

My smoothest idle and best vac happens at about 26*. And too much lead has less negative impact on the idle than too little does.

I find it much more difficult to keep the mech advance from starting until after the idle and then having it all in as soon as possible. Usually 2,000 or so. Getting to that usually requires several distributor dis-assemblies juggling springs and weights.

Dave, isn’t your cam about 20* less duration @.050 than the OP’s 274@.050?

If I’m running a combination that has advance, like you, I prefer to not have the timing change from idle in neutral to idle in gear.
I’m not as fussy about having it all in by 2000 per se, as long as it’s fully advanced a few hundred rpm lower than whatever the low end of the cruise rpm is.

Yes mine is 270@50 and that cam is currently working real nice. Thanks for selecting that spec Dwayne. I currently have a billet MSD with the stiffest springs MSD has and only 6* advance in it. Intitial is 30* and 36* total all in about 2900/3000rpm. Seems to work pretty good but havent tried the weaker springs yet.

My question was actually directed at DaveRS23.

I thought his Hemi was something like 255@.050.

Oops. Dont mind me, but i thought his cam was a 274@50.

Yeah, my cam is small by Moparts standards. 246*/256* FTS.

The all-in at/about 2,000RPM is not set in stone by any means. It is just a target. Maybe I should have said low 2,000s instead.

With 3.91s and the 518, I often cruise 2 lane roads around 2,500RPM. So, as you noted, all-in by then is my goal.

I like my total all in by 2000 rpm. I run a set of light springs and set my total at 36 which it seems to like best. Then I see where the initial timing falls which mine around 21 initial. My car likes that and runs fine with no pinging at all. If I wanted to change my initial then of course I have to change my total in the dist to end up at the same total of 36. Ron

I'd like to get more initial timing in the 340 in the Dart...I'm currently running MSD with the black 18 degree bushing...
Does anyone have experience with these bushings? One is 10 degree and the other is 14 degree...
http://4secondsflat.com/MSD%20Distributor%20Tuning.htm

I have those bushing $10 ea + shipping

CNC'd and the 10 is flat sided already as well to help fit in the window.


Sold quite a few to members here and and FABO, FBBO.

Shoot me a PM if interested.