spark plugs?

sg1747 · #1 11-18-2009, 03:36 AM

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

Chevy454 · #2 11-18-2009, 02:20 PM

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

firez · #3 11-18-2009, 04:35 PM

I have used NGK XR5 stock #5953 in my 68 Z with no fouling problems.

Chevy454 · #4 11-18-2009, 04:46 PM

[ QUOTE ]
I have used NGK XR5 stock #5953 in my 68 Z with no fouling problems.

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

sg1747 · #5 11-18-2009, 05:20 PM

whats the 5034

Chevy454 · #6 11-19-2009, 04:45 AM

[ 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...

**wheelhop** · #7 11-19-2009, 02:26 PM

any similar recomendations for an 1969 L78 motor?

**Salvatore** · #8 11-19-2009, 02:37 PM

I believe there is a whole thread on this a while back. Rob ran down the best choices. Can't find it though.

sg1747 · #9 11-19-2009, 05:02 PM

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

**Salvatore** · #10 11-19-2009, 05:07 PM

John, if they are extended tip that may be the problem. I run AC R44's and seem to do just fine.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Dedicated to the Promotion and Preservation of American Muscle Cars, Dealer built Supercars and COPO cars.