292 tune up question

[69gmc292]

I am trying to find out what people are running their ignition timing, idle, and gap on their plugs at for a 292. My truck is an auto and runs real rough at idle when in drive. I am running an HEI and just replaced the plugs in it for emissions last mouth.

Thanks

[68gmsee]

Assuming it's running rough because of ignition, I'd play with the timing to find the best setting. With the hose to the vacuum advance plugged, I set mine at 8 degrees on my 250. You can start at that and go higher to see what your truck likes.

I've got the plugs at .040 but some guys here prefer .045 -again, whatever makes it run better.

However, after saying all that, you may want to check to make sure your distributor rotor, cap, internal ground wire and all parts are good. Don't forget the plug wires.

There are other things that can make for a rough idling engine including valves and cam, but I guess you have eliminate them one at a time.

Good luck...

[factorystock]

Engine specs are plugs .035 , timing 4 BTDC @ 600 rpm. Other things that may cause rough idle are vacuum leak and low compression. Check intake manifold gasket and carb connections for vacuum. Check compression for worn valves or rings.

[Dark Knight]

Hook up a vacuum gauge to the intake manifold and idle the engine. Rotate the distributor until you have obtained the most vacuum. That will take care of the timing. If you hear any pinging under a load, back the distributor off a degree at a time until it stops.

[zeeklu]

I agree with Factorystock.Intake manifold being loose is real common. Chris