Hi. I recently purchased a 66 coupe 289. The rebuilt engine has about 12k on it. The top end was recently replaced with aluminum heads and a mild cam from skip white competition.

the car has been running perfectly for hundreds of niles with no issue. The cam was properly broke In according to the previous owner.

Here’s the trouble. I replaced the steering box and when putting it all back together, I accidentally crossed the spark plug wires on the front 2 cylinders on the drivers side. I started the car and noticed it running very roughly with some slight sputtering. I started it again for about 29 seconds and shut it off, figuring I messed up the firing order. Yep, crossed the first two spark plug wires, easy fix!

After putting the plug wires back on correctly, I started the car. It fired right up and idles fine BUT there is now a loud tapping sound coming from the first 2 cylinder area on the drivers side, right where I did my wire crossing.

What did I break? Could crossing the wires and starting it twice for less than a minute destroy my motor? I’m not sure what to do. Pulling the head is definitely above my comfort level but I’m not opposed to try. The car actually goes to the speed shop in a week. Any advice is appreciated.

 

It is very unlikely that crossing those two cables could cause physical damage. Did you remove the spark plugs for the steering box swap? If so, pull those again and see if the insulator or electrode is broken on either of them. If not, or you see no damage to the spark plugs, you need to remove the valve cover and wiggle each of the rocker assemblies to identify anything loose. If you find something suspect, include pictures.

 

I re-read your thread on the steering box. Since you had the header off, is there a chance anything snuck its way into an exhaust port? I know, a question without an answer. If there is no other reason for the noise discovered, the next step would be to remove the header again and inspect inside the exhaust port.

 

Or an exhaust header gasket is bad. This is common.