Recommended rpm for 700R to 305 V-6

[jbgroby]

We have the 700R at approx 650-665 rpm, and will play with the timing but we seems to be getting back fire when we shut the engine off. One friend suggested to verify the needed RPM. I dropped on a 700R behind my 305.

Let me know how y'all feel on this,

Thanks
Jake

[Funky61]

You mean at idle? Jolly Page states 450rpm for an automatic. You can probably kick it up some like I did to about 550rpm. I have a manual 4 speed.

http://www.6066gmcguy.com/EngineData.html

[James]

Backfire through the carb when you shut the engine down! That is strange. I don't believe the transmission could cause this.

Having the idle too high might make it diesel when you turn the engine off and causing the engine to kickback (or puff) through the carb.

Other thought-
Does your truck have a "Gen" light on the panel? I have seen in my distance past this was caused by an engine idling to high and the gen light circuit (light would be glowing with the key off) back feeding the electrical system with enough power to make the engine barely run. You can try removing the bulb and see if the problem goes away.

That my thought on it.

[jbgroby]

Thank you.

[AZKen]

It's either too high of an idle or timing. Set motor to specs. This is all provided that carb is built and adjusted right.

[jbgroby]

Ok, well dial down the idle a bit, to see if that helps.