Tuning Problem

[pismorat]

I have a 383 in my '79 pickup and it has been running rough lately. If I stab the throttle from idle, it will studder for a while until I begin to let off, then at about 2000rpm it feels like it "cleans out" and it starts to pull like crazy all the way to 6500rpm. For some reason from idle to 2K it just falls on its face...is this a carb or timing issue or both? It has a .520" lift cam and I run 89 octane, I am off to the desert next weekend so I'd like to get it tuned up by then.

 

[Hogback Fabrication]

Which carb?

 

[pismorat]

Edelbrock 750cfm, this engine has always liked to be a screamer, but this studdering has gotten gradually worse.

 

[pismorat]

OK, now it is worse today. It misses no matter what RPM it is at, so I am thinking distributor cap & rotor, or spark plugs or wires. I'll pull the cap & rotor first, then check the rest...any thoughts?

 

[Hogback Fabrication]

Check your timing.

 

[Thunder]

Might also replace the module while you are working on the dist.

 

[pismorat]

I played with it today, and I could turn the distributor cap by hand, but it took some effort. I think it may be a mix between timing and bad (ARCO 89) gas. Next week I will mess with the timing some more, but also look at the cap and rotor. The plug wires are ACCELL 300+ and are less than a year old with fiberglass shields on the plug ends. I may pull the plugs just to check them out as well, I assume all of the above could be an issue??

 

[GsxrMike]

How fast did the problem progress? If it kept getting a little worse everytime you drove it and you could turn the cap by hand I would say your timing if off for sure.