Plug Options for 427 bb, iron head, street engine
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Joined: May 2000
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From: Midland Texas
St. Jude Donor '09-'11
Plug Options for 427 bb, iron head, street engine
I started out with AC R43XLS which look a little cold for the street and then went to R45XLS which look a little warm for the strip. I think I need something in between. What are my options in other brands in the same heat range span?
Engine is a 427 +0.070, 10:1 JE pistons, small chamber square port heads, Comp Cam Hyd Roller, 870 Holley Street Avenger, MSD 6AL, Hooker 1-7/8" long tubes, 4.11 gear 66 coupe body, 92 octane premium.
I got the MSD wiring corrected and the choke problem fixed, so I am ready to tweak it a little. I've just lost track of the spark plugs currently available for this engine.
Joe Lynch
Engine is a 427 +0.070, 10:1 JE pistons, small chamber square port heads, Comp Cam Hyd Roller, 870 Holley Street Avenger, MSD 6AL, Hooker 1-7/8" long tubes, 4.11 gear 66 coupe body, 92 octane premium.
I got the MSD wiring corrected and the choke problem fixed, so I am ready to tweak it a little. I've just lost track of the spark plugs currently available for this engine.
Joe Lynch
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Joined: May 2000
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From: glendale, ca
Re: Plug Options for 427 bb, iron head, street engine (Joe Lynch)
Hey Joe, I popped in a set of AC R44xls last week. They are right in the middle of the hot and cold plug range. They seem to work great for now, but I haven't pulled them to see what they look like. At $1.50 a piece, how can you go wrong. Forget all those fancy shmancy plugs and go back to the basic, I say. 
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Pro
Joined: May 2000
Posts: 610
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From: Midland Texas
St. Jude Donor '09-'11
Re: Plug Options for 427 bb, iron head, street engine (ARA427L68)
I got to go out and run the Vette some sunday afternoon in the country, running it up in each gear, then cutting the engine and coasting to a stop so I could read the plugs. With the stock jetting in the Street Avenger carb, the R45XLSs were sooty. I leaned the jets down two sizes and the soot was starting to disappear when we went home. I may get to try the set of R44XLSs next weekend. May also have to go leane5r on the carb. This was at 26.5" Hg station pressure, 100F, 23% humidity.
My bet is that the 44s will be just right or a tad cool.
Joe Lynch
My bet is that the 44s will be just right or a tad cool.
Joe Lynch
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Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Re: Plug Options for 427 bb, iron head, street engine (Joe Lynch)
I have good luck with ACCEL 276 normal or 274 one step colder in my 454. They also make shorter porcelian plugs in 276 if you have a header clearance problem. 276S
Norval
Norval
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Joined: Oct 2000
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From: Ft Walton Bch FL
Re: Plug Options for 427 bb, iron head, street engine (Joe Lynch)
I also run the R44XLS plugs in my 468; they seem to be on the money on road trips, and just a tad cold for stop and go. NGK B9ES and B8ES are good plugs too, with the 9's being hotter, as well as the NGK V-power. Sorry, I don't have a number for the V-powers handy. More power Scotty! :crazy:
Safety Car
Joined: Aug 1999
Posts: 4,862
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From: Texas
Re: Plug Options for 427 bb, iron head, street engine (dually4wd)
. NGK B9ES and B8ES are good plugs too, with the 9's being hotter,
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Thread Starter
Pro
Joined: May 2000
Posts: 610
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From: Midland Texas
St. Jude Donor '09-'11
Re: Plug Options for 427 bb, iron head, street engine (Joe Lynch)
Thanks, gentlemen. The local autozone computer data base also showed the equivalents for the 43-44-45 AC heat ranges. I think i am set. The 45s look OK for the street right now, but I won't know until we get the car tagged and proof of insurance where I can drive it a bunch.
Joe Lynch
Joe Lynch
