spark plugs?
 

Just wondering what plug you would use on a 302 that has a true 12.5:1 compression? Right now I'm using racing autolites 133. I don't drive the car alot but the autolites seem to foul the plugs.as soon as change them she gos right up to 7500 rpm.colder plug maybe?

thanks

Re: spark plugs?
 

If it's the original 186 heads, try an NGK R5670-7 (5034)...

Re: spark plugs?
 

I have used NGK XR5 stock #5953 in my 68 Z with no fouling problems. https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Re: spark plugs?
 

[ QUOTE ]
I have used NGK XR5 stock #5953 in my 68 Z with no fouling problems. https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

[/ QUOTE ]
The XR5 would be the standard (non-race) version of the R5670 (race) plug...both are good plugs.

Re: spark plugs?
 

whats the 5034

Re: spark plugs?
 

[ QUOTE ]
whats the 5034

[/ QUOTE ]
5034 is the stock number...R5670 is the part number...and -7 is the heat range. Nearly everyone refers to the plugs by the part numbers (which makes sense), but the parts stores I've been to can only look it up by the stock number, so you kinda need to know both... https://www.yenko.net/ubbthreads/imag...ins/tongue.gif

Re: spark plugs?
 

any similar recomendations for an 1969 L78 motor?

Re: spark plugs?
 

I believe there is a whole thread on this a while back. Rob ran down the best choices. Can't find it though. https://www.yenko.net/ubbthreads/imag...s/headbang.gif https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Re: spark plugs?
 

Well i can tell you one thing all the ngk r5670-7 (5034) got smashed closed.

Re: spark plugs?
 

John, if they are extended tip that may be the problem. I run AC R44's and seem to do just fine. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: spark plugs?
 

The Autolite 133 is a .460" reach, non-projected, tapered seat plug, which crosses to an NGK R5673-8 (3249)...so that should be an exact match. Did you index the plugs by any chance? Also, I was thinking the 186 Z heads used a gasketed seat plug, no?

Here's the chart: click here Do I have the seat type wrong on the small block stuff?

wheelhop: we run the R5671s in all of our 840 headed stuff, and the engines love them...you could try a GR5, which is the standard plug version of the R5671, except it's gonna have the extended tip.

Re: spark plugs?
 

Thanks sam i will try them.

Re: spark plugs?
 

now i have the NGK 5637-8 (3249) short tip and runs great.thats what it was sam it had the long tip.but if this plug gos away i will try the AC-R44. thanks all
ps please not that word index it takes 2 hours on the race car for that.

ASTA

Re: spark plugs?
 

Thanks Rob, I'll give them a try