My girl freind's sons truck is a 91 chevy w/ a 350cu in and the kids have plug wires on wrong and I said I could help well evidently chevy's changed the location of # 1 on the distributer cap.
Cam any ony one tell me where it should be or tell which fourm to go to find this out?

thanks,ramguy

 

The cap is usually marked and the firing order is usually casted on the intake manifold. If the cap isn't marked you may need to pull the #1 sparkplug and find TDC. With the engine at TDC the rotor will point at #1 position on the cap..The #1 plug is front drivers side. Good luck.

 

on the cap if it hasn't been changed the pin for number one will point towards the number one cyl.roll the crank around to tdc and pull the cap and see where the rotor is.it will either be on or 180 off.

 

Thanks guys;
Evidently the distributer off 180 deg then. Thats kinda what I thought, thanks for your help.
ramguy

 

Pull #1 plug and stick your finger into the hole ( note.. don't screw it in, just hold it lightley in the hole). Have someone bump the engine for you while your finger is there and then you will feel a pop, pop, pop as the cylinder comes upto TDC on compression stroke, when you feel no more compression stop and line up #1 on the tower of the distributor and plug wire. This will get you close enough to set the timing.
BUT FIRST make sure the battery wire is disconnected from your distribuitor, the 1991 should have a HEI system and they will give you a nasty bite, somewhere in the 75,000 to 90,000 volt range with a racing coil.
Also if you let them fire without the load of the spark plug the distributor can arc out internally and can be a pain in the butt to diagnose if you do not know about it. It will usually arc and blow a hole between the center HV terminal on the underside of the cap through the rotor cap and ground out onto the advance weights.
Been through many of these.
Hope it helps. Jim.