pmr2000

Would it make it any easier to route the plug wires if I first removed the shields by the block? Or are these things never coming off or go back on if original? I have a 75 coupe L-48 manual never rebuilt, just cleaned up engine.

I am finally ready to take on plug/wire swap and NOT looking forward to it!

Alan 71

Hi pmr,
It's necessary to remove the radio interference shielding, (the chrome plated shields), but not the spark plug heat shields or the "boomerang" shaped shield on each side of the block.
Regards,
Alan

This is a 71 but your 75 is similar.
This is the right side… the left side is similar.
Originally the first 2 spark plug wires passed between the engine mount and the block as they went behind the boomerang.



Left side. Note spark plug heat shields aren't in place yet.

Chinaski

I don't have any of the stock shielding on my car, but a little advice on the plugs themselves...A few of them are a bit of a pain, at least on my car. #2 and #4 specifically because of the AC compressor. But even then, it's straightforward.

Some 3/8 fuel hose comes in handy for threading in the plugs, and I find a 1/4 ratchet with a 1/4 to 3/8 adapter for your spark plug socket is easier to wield in some of those tight spots where a regular 3/8 ratchet is a little 'big'

pmr2000

Would removing the lower shielding be advisable for a weekend cruiser? Is it really needed to protect the wires from the manifold or block?

I just bought stock AC Delco plugs plan to gap at .045 and MSD 8.5 wires that route under the manifolds....

Alan 71

Hi pmr,
Their intent is to hold the wires away from the manifold and against the block. The manifold/head pipe gets much hotter than the block itself.
It's up to you.
Do you think Chevrolet would continue to install it, ($), if it wasn't needed during normal operating conditions?
Regards,
Alan

Chinaski

Is it required? No. You could always put thermal boot protectors and what not, or run wires with ceramic boots.

The only real advantage to not routing them in the stock manner is access to the plug wires in case something goes wrong with one of them. However, if you run them the way the GM designers intended it, there is less of a chance for a problem to occur.

If I was you, I would run them the proper way.

pmr2000

Thanks will keep the shields on.....was looking at other 350's this weekend at cars and coffee wondering why no heat shields..but most had more room in the engine bay.