Re: {Chrysler 300} Ram tuning

That may be just what the instructions I posted was trying to do by taking the idle down to below 600 rpm before timing was set, so there would be no mechanical or vacuum advance applied when initial 5 degrees before TDC is established before reconnecting vacuum and bringing curb idle back to 725-750?

On Thu, Sep 17, 2026 at 11:06 AM dplotkin@xxxxxxxxxxxxxxxxxxxxxxxxx <dplotkin@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

I am advised by a Chevrolet guy, to limit mechanical advance and then advance timing. Has anyone tried that?

Danny Plotkin

-----Original Message-----
From: "John Grady" <jkg@xxxxxxxxxxxxxxxxx>
Sent: Thursday, September 17, 2026 11:58am
To: "John Nowosacki" <jsnowosacki@xxxxxxxxx>
Cc: dplotkin@xxxxxxxxxxxxxxxxxxxxxxxxx, "club chrysler" <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Subject: Re: {Chrysler 300} Ram tuning

note it says zero about use of vacuum gauge how to do it right on idle mixture .

What the hell is smooth idle ? can be way rich

And while sequence sounds nice pretty and easy they all interact

You have to go around again another time, ( or ten) just like you said on air bypass

On Sep 17, 2026, at 11:51 AM, John Nowosacki <jsnowosacki@xxxxxxxxx> wrote:

Slightly long message, but just copying idle adjustment procedure from Service Bulletin 61-10 dated Sept 29, 1960.

Ignition timing to be set to 5 degrees below TDC as this effects idle quality.

Disconnect vacuum advance from distributor as there is full advance at idle, and set the timing with the engine idle speed below 600 rpm, transmission in neutral and A/C compressor off, using both carburetor idle bypass screws until desired speed is obtained.

(no mention made of where to start with position of air bleed screws at this time, I also never noticed/saw this instruction about being below 600 rpm to set initial timing. I wonder what it moves to at 725-750 while vacuum advance is still disconnected?)

Connect vacuum advance and run engine up to normal operating temperature, then turn off engine.

Turn all screws (mixture and air bleed) in finger tight.

Open air bleed screws one full turn.

Open all mixture screws 3/4 turn.

Connect tachometer and start engine (good luck with that)

Turn mixture screws on left carb 1/8th at a time for smoothest idle

Repeat for right carb, keeping mixture screws within 1/8th of a turn of each other.

With transmission in neutral, A/C compressor on, and parking brake applied, set curb idle between 725 and 750 rpm using air bleed screws, keeping adjustment equal on both carbs.

(First time I tried this, the car would not start/idle until I had the air bleed screws both open to around 2 turns, not 1. Once it would idle, I proceeded from there.)

Fast idle adjustment on car is also kind of funny-

Engine should be at normal operating temp and set to 725-750 rpm.

Turn A/C off and remove air cleaners

Disconnect each throttle rod at the bell crank

Open throttle valves of left carb and position fast idle screw on fast idle cam at index mark.

Leave right carb at curb idle position.

Allow throttle valve of left carb to close.

Adjust fast idle screw until idle of 1375-1425 is obtained.

Reverse/repeat procedure for setting fast idle speed of right carb while left carb at curb idle.

Note: There is no specification for idle speed when both carbs are set to fast idle position simultaneously. ;-)

Reconnect both throttle rods at bell crank.

Have fun, if you dare.

On Thu, Sep 17, 2026 at 10:07 AM dplotkin@xxxxxxxxxxxxxxxxxxxxxxxxx <dplotkin@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

As you know the owner's manual supplement, the one that admonishes the driver to respect and control its power with care explains that the specified high curb idle of 750-780 RPM is necessary because of the big camshaft.

Every smart engine guy I know (non 300 type) looks at my idle as way high.

When I got the car someone had the idle down to where it might be on an Impala 327. The engine would struggle to carry the RV2. Mr. Verity raised it and its great, except for the whack to reverse.

I think the engineers did the best they were willing to do, they likely concluded we only sell a couple thousand of these a year, the owners will put up with the idiosyncratic behavior, it is, after all high-performance motor. Let 'em trade it for a New Yorker if its civility they want.

I think Tom Hoover came up with Max Wedge precisely to do away with these giant pipes, hard to tune, make the car hard to work on, expensive castings, iffy drivability, dissatisfied non hi-po seeking customers.

I love them for all that!

Daniel D. Plotkin

Daniel Plotkin & Associates LLC

54 Capri Drive

East Longmeadow, Massachusetts 01028

413 237 9629

dplotkin@xxxxxxxxxxxxxxxxxxxxxxxxx

-----Original Message-----
From: "John Grady" <jkg@xxxxxxxxxxxxxxxxx>
Sent: Thursday, September 17, 2026 8:37am
To: "chrysler 300 club" <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Subject: {Chrysler 300} Ram tuning

This is an old subject but years have gone by and those interested in this , some pretty smart guys have gotten in pretty deep ..... I have " tuned " a lot of rams over the years and surprised by variability in final outcome . Despite a lot of effort, some cars kind of fight, you a few settle in.
This is not about obvious stuff we all know , it is about things rams do at times. Maybe all times , more or less . And some on site have really gained significant knowledge over past 20-30 years
I have one fighting me now , the constant fight between stable rpm at idle and slamming into gear and then stalling. As if idle has no torque if " loaded up" They even mention this " rough engaging" in user guide on F .
Part of it is due to unported vacuum to ignition , always full advance at idle . If vacuum drops ,at trans engage, ( it does) ignition retards = stall . I mean this is real and anti stall thing grew out of it, but opening throttle more just off idle drops vacuum more . Thin line there . And I think design is flat out wrong we have to tune around it .. I was thinking ??? add a small vacuum can and orifice to slow down advance action , or buy carbs with ported vacuum like every single other car the world has . Carl did that his car runs great . AVS calls to me ..
The second thing is the tendency to stall off a stop sign depending how much you feather pedal .
It feels like it goes lean momentarily ( remember this is some cars not all)
So seems like carb squirt is either late to the party with small thrittle motion startup off idle , not enough gas , or idle mixture wants to be richer than optimal ( as set by vacuum gauge) to cover this transition It us really bad puling into traffic and car suddenly stalls, adds stress to driving . This is tangled around issue 1
I am ignoring warm up issues , another whole thing , but gets into this in first 15 minutes

Lets call it ole ram guys , philosophy etc .

Can be made to be acceptable , yes, but really optimal -- no, not easy to get to . And how about ignition timing ? they say "no spec for that idle timing with vacuum on , just set with off" .but it IS on st idle . And high , ? leading to above sensitivity to stalling slamming all that
Deep thinkers on this , insights gained welcome ..
J

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