Curb Idle Settings 1969 350/300

[Erv M.]

In the 1968 - 1972 Operations Manual & PV Test Guide my 1969 350/300 with automatic transmission curb idle should be 600 rpm with a Fast idle of 1,800 rpms.

Question #1 - curb idle is this with the car in park or drive as they produce different rpm ranges?

Question #2 - Fast idle is with the intial cold startup with the choke fully engaged and as the motor warms the rpms should drop, is this correct?

[Terry M.]

Re: Curb Idle Settings 1969 350/300

#1 - with load on the motor -- car in Drive and your foot on the brake.
I think if you try to set the idle to 600 in neutral and then put the trans
in drive and your foot on the brake -- the engine will be on the edge of
dying or maybe even dead.

#2 Yes

[Duke W.]

Re: Curb Idle Settings 1969 350/300

The AMA specs should have what you want. "Curb idle" usually means neutral with a MT and in Drive with an AT. The Ops check/PV instructions should be clear on this. If not, they need to be revised.

If you don't touch the throttle the fast idle cam will not back off and idle speed should increase with time. Once you touch the throttle after the first couple of minutes of operation the fast idle cam should relax and fast idle speed will go down with throttle movement as the engine warms. Some fast idle "cams" are actually cams, some are stepped.

Duke

[Stuart F.]

Re: Curb Idle Settings 1969 350/300

If you live in Florida or are doing your settings under high ambient temperature conditions, you may have to position the high idle set screw on the index mark of the cam by hand. Normal choke settings usually will not give you a full closed choke on startup - specially with older automatic chokes with choke springs that may have lost some of their tension over time and use. An electric choke will usually do a little better in this regard. I have an aftermarket kit I've been testing with mine and it will give me full closure on startup, even in the heat of the summer, then relax at a more suitable rate during engine warm up. You don't have the slight hot air bleed provided by a regular choke, but then that only amounts to around 1.5" to 2.0" hg vacuum pull anyway which is insignificant. It is enough to still give you a functioning choke pulloff.

Stu Fox