"I run block huggers. Had to go with NGK plugs. They are shorter and your plug boots don’t melt. On mine anyway. 350 ci."
Beltfed,
I'd seen "header plugs" advertised so I checked to see if the major plug manufacturers also make short plugs. In figuring out what plugs my roadster engine liked I tried out both Bosch and Champion short plugs in various heat ranges that are standard equipment in common applications and are inexpensive at auto parts stores. The ones in this photo are Champions and as you can see they provide good clearance for the plug boots in the tight spots, cylinders 1,2,7 & 8. These plug wires from Summit Racing are about 15 years and 23,000 miles old and there is no sign of the boots and wires getting toasted by the headers. So there are choices in short plugs for header clearance.
Also on this subject we are often told on this forum that headers are chronic leakers. The headers in this photo have never leaked and they are fastened by plain old stainless steel Allen head bolts and stainless steel lock washers from a local hardware store, nothing fancy. If you look closely you'll see that 2 of the bolt heads on each cylinder bank (cylinders 1 & 7 in this photo) had to be slightly machined to create clearance at the exhaust tube. That was a 5 minute job on my lathe.
