Nitrous Spark Plug help

Slow91

New Member
Nov 9, 2018
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Salt Lake City
Hello guys! I am pretty new to nitrous and need some input. Recently bought a 5.0 that Is running 150 shot of nitrous. Cars been running great, its just time to change the plugs. Car is a 306 built motor, aluminum heads, cam, etc. What plugs do you guys recommend? Talking to the previous owner, he said he couldn't remember what plugs were in it, and said it was gapped at .28. I feel that gap might be a little off? Car does run great though. Any information will help!
 
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Well I guarantee the gap isn’t .280, as that is over a quarter inch. Probably more like .028, which is acceptable for nitrous. Should be able to get a little more gap with only a 150 shot though, but I wouldn’t push it if it runs well.

Without knowing the head, I’ll guess it takes something like an Autolite 3924 plug. I’d put an Autolite 3922 in there for nitrous, although it will want to foul a little quicker, If you’re not spraying.
 
id also suggest running NGK over autolite...

you ever want to start leaning on the tune up you'll melt a piston before an autolite... but an NGK will melt before a piston
 
For some reason when looking up the spark plug it says it would not fit a 5.0. Is that incorrect? I used NGK R5671A-8 as the part number. Would there be any difference at all gapping the plug from .028 to .030? Or .028 to .035? Any information will be great! Thanks!
 
The early model GT40x heads use the same plug as a stock head. The later models us the Autolite 3924 plug (Autolite 3923). I run a 3924 with nitrous, it's fine. The NGK is a TR5 plug.

Kurt