06/04/2013 "How I Do It"

Crafting a set of spark plug wires for the 300J/Ram K

by Carl Bilter

The 1963 300J and the 1964 Ram K were equipped with a cross ram engine that was unique in many ways among the letter cars. Among the unique aspects under the hood was the spark plug wires. The wires are not same color or configuration as those on the F and G ram engines. The wire routing is also different. Some of the wires on the J/Ram K were also heat shielded near the factory cast iron exhaust headers as well. Correctly reproducing the plug wires is not a simple task.

The J/Ram K wires used a unique "orange/brown" color 7mm wire that was shared with the max wedge and race hemi cars. This color wire is not available in bulk wire or ready made sets from the typial suppliers. If money is no object, what appears to be a correctly reproduced wire set for the J/Ram K is available from Lectric Limited as illustrated to the right. These wires appear to be the correct color and configuration but are very expensive at $950.

Atlas Obsolete also offers a ready made wire set for the J/Ram K at considerably less cost. However, the Atlas set is incorrect in that they use black color spark plug wire.

If you make your own plug wires as I do, you can craft a suitable set for the J/Ram K albeit not 100% correct in color. As the "orange/brown" wire either needs to be custom made and/or is very expensive, a reasonable substitution can be made using regular orange wire (which actually isn't all that easy to find any more in 7mm width). I found a universal orange "retro" radio suppression wire set from Summit Racing, part number SUM-G829, that worked well for me. The best part is you can make up the wire set for only about $65 or so. If you always make up your own spark plug wires, investing in a professional crimper is a wise move. I use the MSD #35051 heavy duty crimper.

The Summit wire set will include straight distributor boots and coil boot in black and the distributor terminals in brass. The wire set comes with incorrect black spark plug boots already attached. You will need to cut those off and replace them with orange spark plug boots. The J/Ram K used 90 degree plug boots on plug #1, #5, #7, #2, #6 and #8. The plug boots on plug #4 and #3 were "obtuse" angle boots. I purchased the six orange 90 degree spark plug boots at O'Reilly Auto Parts (BWD part #CT516) and six 90 degree spark plug terminals (BWD part #CT518). To create the "obtuse" angle boots, I purchased two orange straight plug boots (BWD part #CT515) and two "bendable" spark plug terminals (BWD part number CT530). The bendable plug terminals will allow you to create the correct angle of about 150 degrees for the boot on plugs #3 and #4.

You will need to cut the wires to length as you assemble them. The Summit set has wires that are adequate length. The wire for #5 plug will be the longest. You will need to use heat shielding on wires where the wire crosses the exhaust headers. You can get heat tubing from Accel, Summit and other suppliers. To determine the correct wire routing, I have scanned factory photos from the J service manual supplement. Wires #2 and #4 are routed over the passenger side valve cover from the distributor cap. Wires #6 and #8 take the scenic route and are routed under the rams along the valve cover towards the rear of the engine and down to the plugs. Note this is different routing for the #6 plug than the F/G plug wires, and it is due to the use of exhaust headers instead of the log style exhaust manifolds. Wires #1 and #3 cross over to the drivers side and are routed down to the plugs over the valve covers. Wires #5 and #7 also cross over to drivers side valve cover, but then are routed along the valve cover towards the rear of the engine and then down to the plugs. The coil wire uses a black coil boot and black distributor boot. 1963 was the first year that the distributor boot for #1 plug was black instead of red.

Back