MDTAHOE

If you are not careful that is very easy to do. The last one I did I was about to put it back together when something told me to take another look and good thing I did # 4 and #6 were switched. Does your scan tool show misfire data if so if you have 2 missing on the same side missing that maybe what happened. Did you have the push rods out? Something caused it to bend they do not bend for no reason. Cylinder may have fired at the wrong time causing detonation. Unless you had the push rods out then maybe it was not in the rocker arm properly or the valves were adjusted wrong. You may have a couple of things contributing to your problem

DarylH

My scanner does show that information now that I've updated it, I'll review it and see what it says.

No, I didn't take the valvetrain apart, just the intake assembly. I was guessing detonation also, although I did find 2 other rocker arms needing a little tightening. So, I also bought fresh rocker nuts with the new pushrod and replaced all of them this morning.

Is there somewhere that I can find a schematic that shows the correct injector layout?

BTW, thanks for your continued help, I really appreciate it!!!

MDTAHOE

If I remember correctly the metering body (where injectors attach) is labeled

in2pro

It is, the manual also references the metering body as numbered for poppet placement.
It also suggests you ensure the poppets are fully seated into the casting sockets, so its possible even if you got the order right they might have popped out if no fully seated

DarylH

Well, I pulled the upper off and the poppets are all fully seated and in the proper port for the numbered cylinder from the metering body (yes, you are both correct that the metering body as well as the lower manifold are clearly stamped which is which).

The scanner shows that #5 & #7 are showing many mis-fires (hundreds), so I'm planning on going ahead with the new cap and rotor. I'm looking at either the Accel or the AC Delco - any recommendations?

Any suggestions on others things that I might look at while I'm at it?

Thanks for your continued patience and support!

in2pro

OEM parts are almost always the best way to go...
5 and 7 are both on the same bank and also right next to each other
that suggests that a possible cross firing or miss-wired at plug or cap.

Also check the wiring for the crank shaft position sensor, make sure its not getting too close to the plug wires, it should run along the passenger side of the engine to the front and down to the crank shaft the reason I suggest this is because on my 97 I had similar issues, turned out the crank shaft position wire harness had come loose and was melted by the exhaust manifold and was shorting out.

in2pro

Im guessing you have already explored these....

A code P0300 may mean that one or more of the following has happened:

Faulty spark plugs or wires
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve
Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages
Faulty camshaft position sensor
Defective computer
Possible Solutions
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

MDTAHOE

I would definitely double check the wires for a cross. A cap is a cap. Any brand will work the same unless it is the absolute cheapest piece of junk out there.

73shark

Not sure if this pertains to the current SBC engines but the old style used to fire #5 & #7 one after the other, so plug wire routing could be critical if the wires are old and start breaking down.