900 RPM idle

[Paul_G]

The factory under hood engine tag is still there. 1973 Charger, 400 4bbl, 4 speed. It says the idle should be 900 RPM. That seems a little nuts to me.

 

[Don Frelier]

Beginning of the emission era.
You can probably set it at 650 RPM with no issues.

 

[4mulas]

900 would be a lot easier in the cam than 650.

 

[Michael_]

900 would be a lot easier in the cam than 650.

That's probably a great idea for the new 5.7L hemis too

 

[Don Frelier]

900 would be a lot easier in the cam than 650.

The specification was not set that way to protect the camshaft.
In 67 the specification was 650 rpm.
I've run my charger at 625 for 30 years with heavier springs than the original.
No issues

 

[beanhead]

Personally I prefer a faster 'racy' idle on a performance engine, 900 would be just fine.
That said, the '73 400 was NO performance engine...they probably needed to idle that high to keep from stalling with all the vacuum-leeching accessories and smog equipment.

 

[Crackedback]

If you aren't subject to smog testing, throw the factory specs in the garbage and tune the engine for what it wants.

It takes some work altering mechanical timing, etc, but, the benefits are great.

 

[Don Frelier]

Personally I prefer a faster 'racy' idle on a performance engine, 900 would be just fine.
That said, the '73 400 was NO performance engine...they probably needed to idle that high to keep from stalling with all the vacuum-leeching accessories and smog equipment.

I don't have a tach in this one but it's well below 900 RPM.

 

[Ironbuilt]

Is that 900 RPM in park or in gear? 900 is about right in park or neutral, but too high in gear. My big blocks idle around 900 in park, and would stall when put in gear if the idle was 650 in park. I have lumpy cams and high compression in both of my 440's.

 

[Crackedback]

Is that 900 RPM in park or in gear? 900 is about right in park or neutral, but too high in gear. My big blocks idle around 900 in park, and would stall when put in gear if the idle was 650 in park. I have lumpy cams and high compression in both of my 440's.

4 speed which makes things easier

 

[beanhead]

Mine rolls around 850 in gear, it's got a little bit of cam..


900 would be high for a stocker. I'm betting back in the day though with small pipes, log manifolds and enclosed air cleaners average folks didn't notice the difference.

 

[4mulas]

Some people like to crank their rpm low to ‘hear’ the cam. Way too low for me. 800 at a minimum. Have a fresh motor now, it won’t see less than 1000 until things are well run in.....

 

[camgrinder]

long periods of low idle are hard on everything, especially camshaft.
Low idle means low oil pressure, hard on bearings, most carbs are not that efficient at low rpm's

 

[Kern Dog]

Is that 900 RPM in park or in gear? 900 is about right in park or neutral, but too high in gear. My big blocks idle around 900 in park, and would stall when put in gear if the idle was 650 in park. I have lumpy cams and high compression in both of my 440's.

Believe this ******. He tells the truth.

 

[Kern Dog]

 

[61-63]

I'm mainly an early 60s Pontiac guy but I like the Mopar Cross ram 413/426 wedge cars too. Dk where they set idle on the max wedges but Pontiac's instructions for the '62/'63 421 Super Duty cars was to set the idle at 1000rpm. Those were solid lifter dual quad 11-13cr engines in those cars. Probably has nothing to do with this thread I thought I'd just throw it out there.

 

[440rb]

900rpm? err don't think so, my 440ci race car idled@900rpm and that was with a .650" [email protected] sft cam ok so you could count the cylinders firing but it idled there fine with an 850DP on top.