This might seem like an easy one, but I'm curious what an acceptable idle speed is for my 440.

Right now, it sits at around 600RPM and seems happy. Vacuum is a little low (15"), but the truck charges and idles nicely.

Is there a certain point that you settle at? Do you try and get it low enough relative to vacuum, charging amperage, and cooling ability of a mechanical water pump?

Thanks for the help.

It depends on cam, oil pressure and all the other things you mentioned. If it idles OK, charges, cools and has 20 lb or more oil pressure at 600 RPM then its good. If not, bump RPM up a bit.

Pat,

If it is an automatic, I personally like them to creep a little when in gear at a light so that I have to gently hold them on the brake. With a stick car it does not matter as much.

Generally it is dependent on the cam, carb and the whole set up.

It sounds like you are in the ball park.

Thanks for the input guys. Glad to hear I'm not too far off on this one.

Oil pressure is nice and high at that speed, charging is sufficient. The only thing I might concern myself is cooling at this point, but that could easily be attributed to a number of other factors (that I'm aware of and working to repair).


John,

I'm still working on that timing issue. Just got the bugs worked out to where she's running pretty nicely. Hope all goes well on your business trip, and I look forward to getting in touch with you when you return

wherever the tune/combo let's the idle speed fall!

for automatics with tighter torque converters, maybe bump it up a few hundred RPM to keep it from stalling when in drive at a stop light, but otherwise, let it idle where it wants!

mine idles around 750 with 25 psi oil pressure when it's hot.

mines around the 500-750 mark

rev it up and it comes back down fast and smooth to the idle

sits and purrrrs

mine also will warm up around the 200* mark if i let it idle for 45-60 mins sitting there with the tranz in drive and pumping fluid

I put a big fan in front last time and it stayed on the 180-190 mark on the t-stat for over an hour

i am looking to fin a 7 blade clutch fan for it though,the 5 blade looks compaired to the 7 blade on the SB truck

i would call it good

In the old days I liked them to just creep in gear with a stock convertor too.
Nowadays though with the bad oil and cam failures I set them up to idle as high as I can stand it so they don't shake the whole car dropping it into gear. Higher idle speed is better for cam life.

Sheldon

I like 900 to 1000 rpm in neutral hot idle.

i like it a bit higher also 850 to 950, more oil to the cam