I have a 276 8ba, l-100 cam, 2x2 Holley 94 with .049 jets and 4.5 power valves. Running gm distributor and Bosch coil. Vintage edelbrock heads. I currently run NGK B6HS. I am having an intermittent misfire and wanted to try a hotter plug. I read that guys run the autolite 216, but that's. 7/16 plug. Would like to stay with 1/2" reach. I can't seem to find NGK b4hs plugs. I can get Autolite 275 but haven't seen anyone suggest running these. Are they too hot? Sent from my XP8800 using The H.A.M.B. mobile app
I don't think that's you problem.Have you checked everything else out ,battery voltage to coil ,ignition switch. What compression ,fuel pressure and timing.Why do you think the heat range is causing and intermittent misfire?
Are the plugs fouling? If so, the next question is whether this is due from the wrong heat range, or more likely from an out of calibration carburetor?
New battery,new coil,new generator, new voltage regulator, 2lbs on the fuel pressure. No vacuum advance running as much advance as I can without pinging. 160 lbs on all cylinders. Valves adjusted to .014". Full 12v to coil. No charging issues. Running 13:1 air fuel ratio on average. Just wanted to try a hotter plug. Can't get b4hs here so I thought I would try the 275 Sent from my XP8800 using The H.A.M.B. mobile app
Ordered the 275. When they arrived they measure way longer than the B6HS. Measured the 216 and they are really close to the B6HS, so I will give them a try Sent from my XP8800 using The H.A.M.B. mobile app
I have the earlier motor That’s built. I went with Champion H 12 Was using old stock H 11.till I Ran out. But the H 12 works great for me. And is a current plug they make. Just a thought you might want to look into
Got the 216 but they won't work as they have a fixed nut and I can't attach my plug wires. Back on the search Sent from my XP8800 using The H.A.M.B. mobile app