My69

Does anyone know the proper plug gap when you run and MSD Ignition. There literature says to add .005 to .010. Does anyone have a more exact recommendation

zwede

I read some webpage on MSD's site that said for naturally aspirated engines running up to 10:1 CR you should gap at 0.050 to 0.060.

467-Ratman

In the instructions they say to gap your plugs at between .050 and 0.60, I have mine set at .050 and seems to work well. With my old GM system I used the old standard of .035 but I guess with the extra juice available from MSD you might just as well light the camp fire with a bigger flame!

AlwaysWave

with an 8.5 compression ratio, MSD 6A, MSD Wires, and a Pertronix, and Rapid Fire plugs, I found 045 to run best.

cardo0

:nono: I can’t find his book right now but I recall old Smokey said .050” for a high voltage box and nothing to gain beyond that. Also keep all wires ½” apart minimum with that high voltage ignition. The #5 & #7 wires need separation the most (18436572) and should only cross at 90* if possible to prevent induced misfires. He talks how surprised he was to find how many pistons were destroyed by misfire when something else was blamed for it. :conehead

gdh

I have 10.5:1 with the same MSD6AL, MSD wires and Petronix with the accel shorty (header) plugs. I have not chenged the gap from the box setting of 35, my question is this: what difference would I feel by going to a 50 or 60 gap, would it be at the lower rpm range ie. 3500 and under. This is something I just never considered when I bought the MSD from a fellow forum member.

AlwaysWave

At 060 my 350 had less of a torquey feel at WOT. The 0 to 80 time seemed to be more than before. Over time I gapped down to 045 and it runs pretty nice. The wider gap is supposed to help ignite the mixutre faster and better.

71coupe

Too much gap will shorten plug wire life. No need to run super big gaps unless go have a lean/low compression motor. I set mine at .040".

gdh

thank-you for the reply, will get on this next week as well as rejet my 750 Edel Perf. carb from the factory settings.