Technical spark plugs for a SBC Blown

I need some help picking out the right spark plug for my application. I have 1976 sbc thats 383 ci. aluminum heads and a 671 GMC blower. what do you guys recommend for that engine and its street use only....Thanks for your help.

 

You need to start with the correct style spark plug that will fit your cylinder heads. For a street engine I tend to start with the heat range for the year of the engine and adjust from there.

 

Do as saltflats said. You will have to adjust the heat range for your blown application .

 

I sent NGK an e mail asking what they recommend and they answered right away. The amount of boost you are running influences the plug heat range. For my big block with 8-10lbs of boost the suggested a plug in the 5 heat range.


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I agree with saltflats, too. But maybe consider a slightly smaller plug gap for the blower.

 

For street use with a blower, use the same plugs you'd use without a blower.

If you decide to go racing, might drop one heat range number.

 

NGK V-power 7

Aulis

 

like Squirrel ^^^
The Information posted in not enough.
Is it a stock Engine with heads & 6:71 added?
Yes 383 ,
how is the short block built ?
What Brand & Model / series heads?
Whats the static compression?
How much Boost ?
( lose blower or tight ?) ( tefloned,Delta)
Then Static compression pulse boost =?
What Fuel grade / type ?
(10% ethanol, none E, octane)
What type ignition are you running?
There are more questions that need to be asked, to have a trouble free tune , besides plug choice.
I do not know of any one who would have a Blower/ Huffer / supercharger that would Not hold Wide Open for a Least a 1/8 of mile @ least 1 time every time driven !!
All name brand head manufactures have a plug chart as a start point , then you need to know about how much total Compression would be under boost.
The 6:71 are the Rotors /lobes removed.
I have seen people do this to give the look sound of the blower wine
( air trapped between belt teeth & pulleys)
But case empty. ( No rotters)

I have had good results with Ac, Autolite, NGK , different plugs manufactures for different applications,
Sometimes different heat range in different Cylinder's.
Naturally aspirated ,Blown ,nitrous oxide , alcohol, gas

 

Are they tapered seats or gasketed plugs ? 3924 Autolites are my go to gasketed plugs.

 

not many places in town I can run over 100 mph....sorry to disappoint.

 

Down shift. You will probably have to go a step or two cooler. What will you be running for fuel?

 

Darn !! I would figure out yr way (West)
Plenty of places that are a 1/4 , 1/8 for the Pull ,1/8 to stop!
When you ran Drag week here on East in Va ,md. Im near all the track's that U ran 1. -to 1-1/2 hrs Except Englishtown.
Yes For Me its getting Harder to Make a 1/8 pass @ 100 to 107 mph (the speed in 660 feet ) with Borla RX1 header mufflers over the front Fenders in My 30 Ford ,the sound travel almost 1/2 mile away @ night , Even on I-95 @ 12:00 am , & there is two Exits with in 2 mile 's ,there is Rarely a gap in traffic to make 1/8 pull from a stop . 20 years ago we would race on I-95 & US Rt 1 between Marine base & the courthouse south.
I just can not Think of Others or my self not making a pass in there ride @ least 1 time when they take it out ""Safely" away from other drivers

 

The other thing, aside from being stupid illegal, is there aren't many places I'd feel safe driving my car over 100 mph, besides the drag strip. AWB cars can be exciting

 

Not hear to argue or make enemies!
I read most of what you post.

We as Humans are Stupid for Trusting any thing out side movement of our legs

Illegal , we could debate that term.

Feeling safe @ a track , thats a personal feeling that a person has about their surroundings or a place.

working @ race tracks from age of
11 /12 to present ,
Its a Dangerous place as a spectator worker or participant.
Being in Flag stand over hanging the track
Or standing on starting line (the tree)Top fuel down threw all categories.
Shut down Area ,
Being on the premises is Dangerous,
& Yes driving a AWB , Short wheel base
94 to 125 inch can be "Exciting "even a 125 inch WB over 210 mph 20 years ago.
I do not drive fast or do a run around others on the Highway or streets , Nor houses , intersecting roads, road ways.

 

Thanks for all who replied. I just found out that NGK, is about 30 min's. from me so tomorrow I will call and see if I can talk to a tech person..

 

If you have a Name brand heads, the manufacture will have a plug chart , If you call NGK you will need to provide them information about yr combination, they will need to know yr plug reach .