92 F-150 302 EFI spark plug issue?
 

Okay I have a question on spark plugs, for some reason last week when I went to buy some ngk spark plugs the threads were not long enough to reach the threads inside the heads, now I finally found some plugs that would fit and thank god they were autolites. I figured I couldn't have NGK's I better get the next best plug and that is autolite plugs with the copper cores to them so the parts lady took about 15 minutes to try to find the right plug for my truck. Why would Ford make different style heads, because those ngk plugs should have fit fine. I tried bosch and they had one style that is called for on my engine, so bosch and autolites had the right style plugs, but I just think it's weird I had to buy a weird style plug to get down there in the heads to thread in??? :) Any answers guys?