It's SOP to inspect & gap new spark plugs to your desired gap before installing them. They could have been dropped, thereby changing the gap, etc. NEVER assume they are gapped correctly out of the box. How does the manufacturer know what YOU are going to gap them at?
Here's the problem, the stihl setting gage seems to set the air gap too tight, like 0.004" measured between the ignition module arms and the flywheel magnets using a feeler gage set. It seems as though the center coil pick up on the ignition module has a wider air gap. Now my question, what is the proper way to measure an ignition module air gap?
Stihl Ignition Module Air Gap... - Arborist, Chainsaw & Tree Work Forum
The deck lid is slightly curved as well but probably only has about a 1/32nd gap in the middle, but combined with the 1/8" gap on the quarter it causes a noticeable problem. I tried using a 5' long wood clamp I have to pull the quarters together at the middle of the trunk opening and they wouldn't budge.
I decided to a buy the AFR 4910 intake for my 502BBC with 265 AFR heads. AFR advertises the 4910 as the ultimate out of box match for their oval heads. For the record here are some of the measurements compared to an Edelbrock RPM Air gap 7516: AFR 4910 Intake, port height --- 1.94" RPM Air...
BBC Intakes ---AFR 4910 vs Edelbrock RPM Air Gap - Team Chevelle
I have a Blueprint Engines 502 and I’m debating whether to run a dual plane performer rpm air gap or a single plane victor jr. Normally I’d slap the performer rpm on it and be done because it’s mostly a street driven car. However, Blueprint dynos these with their version of the victor jr. and...