RPM- Iddle issues
 

1970 C10 p/u 350 5.7L with a performance cam, edelbrock 600cfm carb, Timing set at 12 BTDC.

My issues is this:
In park idle is runs about 900 rpms. I let it warm up to optimal operating temp and once I shift to reverse the rpms dramatically drop to 300 or so for a bit before it comes up to 500. Once I get going it runs well. BUT when I come to a stop light the RPMs drop to about 300 and the truck sounds like it wants to stall before it kicks itself back up to 500 rpms.

I have checked timing, vacuum leaks, accelerator pump, jets, springs, spark plugs/wires and so on.

I am at a loss as to what I need to do next. PLEASE someone help.

:banghead::banghead::banghead::banghead::banghead::banghead:

Re: RPM- Iddle issues
 

What size "performance cam"? Is the converter matched to handle the rpm range of said camshaft?

Re: RPM- Iddle issues
 

Modulator valve in the transmission. (?)

Re: RPM- Iddle issues
 

Lower,
The cam was specially made and grinded for my truck. I am not sure of measurements BUT it was all installed when the engined was rebuilt. I know for sure that the converted is made for the engine and cam.

Re: RPM- Iddle issues
 

This whole issue started after I had a mechanic install a new intake (edelbock air gap dual plane intake) I am wondering if maybe he did not install the distributor correctly when the engine should have been at TDC??? COuld a misaligned dist. cause this type of issue?

Re: RPM- Iddle issues
 

All that was installed brand new way before this issue started.

Re: RPM- Iddle issues
 

If you checked the timing and it is ok then the dist is probably fine, did he get the vacuum lines to the trans and the dist hooked back up in the right places?

Re: RPM- Iddle issues
 

@Lower

Yes, but I asked him a few days ago how he adjusted everything and he stated that he could not see TDC and so I am not sure if he put the dist in without it being aligned properly.

Re: RPM- Iddle issues
 

If you know how to find TDC, roll it up there and pull the cap and see where the rotor is pointing.

Re: RPM- Iddle issues
 

Try putting ported vacuum to the vacuum advance & then turn the idle speed screw up till you get about 800 rpm idle speed in neutral.