Daniel Boone

I recently purchased a 75 Delta 88 with a 455. It was running rough so after replacing the plugs I decided to replace the plug wires too. I had a heck of a time trying to get the plug wire lengths to work out. They are connected but don't seem to be the correct lengths even after much switching around trying to put the shortest wire on the closest plug and so on. The replacement set of wires were different lengths than the wires on the car. I called AC DELCO and verified how long each wire was supposed to be for the 455 and the new set agreed with their measurements. Anyway I decided to get a GM manual. I have found conflicting evidence as to where the rotor should be pointing when ready to fire number one cylinder. One location says the rotor should be pointing at the drivers seat area and another diagram shows number one to be one hole to the right of center closest to you when facing the engine from the front of the car. (i'm sure thats as clear as mud). Anybody out there with a 455 that can tell me how theirs is set up? Anybody out there with a 455 willing to take some close up pictures that will show the plug wire routing and the vacuum hose routing including the cruise control vacuum?
Thanks

liquidpower

this should help its from the hanes manual
CIMG1690.jpg

Olds64

There is no right or wrong way to route spark plug wires. Any spark plug wire set you buy at a parts store is going to work for about 100 different cars. The best idea when routing spark plug wires is to pull them off one at a time and replace them with the shortest one that will work. If you don't like the way the wires are routed right now try using some wire looms you can get at the parts store. This will keep the wires out of the way. You can also use zip ties to tether them together if you are cheap.

Jamesbo

I've always just laid them out on a table like so.


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csstrux

I always liked using zip ties if I was trying to be fancy. If you use the small ones spaced about 1-1.5" apart you could get some nice straight lines, and tight angles. A bit of time and effort would produce a clean look.

joe_padavano

Normally you should not run plug wires exactly next to each other. This can lead to cross fire, particularly between the no. 5 and 7 plugs on an Olds firing order. That's why the factory used separators.

csstrux

Learn something new every day

dan2286

I have done that before and I ended up with a two wires that dont match with anything They were the wires from my 307, I dont know why they were that way.

citcapp

First thing in my mind is to check and make sure that number one cylinder is at top dead center on the compression stroke (both valves closed) and then check were the rotor is pointing. If the distributor has been replaced the firing order could have number 1 rotated to a few different locations. My 455 distributor rotor points at the number one cylinder when at top dead center. It was set up that way when I rebuilt the engine. Firing order is the same

Daniel Boone

Thanks for all of the responses. I did try to match the lengths of the wires from the new set to the lengths of the wires on the engine. The wires coming off must have been custom made because they did not match any in the new set. I think "citcapp" is correct and someone has overhauled this engine changing the direction the rotor points when firing number one cylinder. Because the rotor on my 455 also points toward the number one cylinder at top dead center instead of at the drivers seat as in the illustration provided by "liquidpower". By the way thanks for that diagram. Question for "citcapp"-did you use a factory set of wires or did you make your own plug wires?

Thanks, Dan

Yellowstatue

I have found that a points distributor rotor points to front left on a '68 and an HEI dist. points 180 degrees opposite??? '75 because they changed the pattern of the wires

Olds64

BTW, what type of spark plug wire set did you buy? If it was just O'Reillys brand then don't worry about it. You can always get a build your own set; however, I've never liked the quality of these.

citcapp

I used a 8MM MSD set of wires that you install the spark plug end on after you custom fit the length. I am very pleased with the way they turned out and perform. My whole ignition system is MSD and I am pleased with it as well

Olds64

I used one of those MSD sets and wasn't impressed. I bought a set of 8.5mm Taylor spark plug wires for the engine I am installing this spring.