67 HP 327 Spark Plug

[Salvatore I.]

I am going to tune my 67 327/350. But before I do, wanted to get some advice on the best plugs to use. I have AC Delcos in the motor now (R type as there is a radio and all of the correct engine shielding is in place). I have been looking at champion as a replacement, denso or split fire plugs...

I drive the car as much as I can, which mostly limits it to every weekend and do a combination of highway and street driving. I tend to not just start the car and move it from one end of the driveway to another, if you follow me. The car is not a trailer queen. I need a mid-range plug, given how I use the car...

Can I get some advice on the best choices to go with and the numbers of the plugs? Thanks for the suggestions....

[Tom Merkel]

Re: 67 HP 327 Spark Plug

Sal - I use OEM AC R43's or 45's in the same L-79 that you have. It's a driver, and not a trailer queen, either. Runs like new. Power, start-ups, cruise. Perfect.

Stay away from extended tips; they didn't work for me.

Tom

[Wayne K.]

Re: 67 HP 327 Spark Plug

Sal,

For all around driving I've had good luck with a 45 heat range plug. I prefer extended tip plugs ever since I kept having fowling problems with regular plugs in a LT-1 I previously owned. I've never had a fowled plug with an extended tip. Just my personal choice.

Wayne

[Duke W.]

Re: 67 HP 327 Spark Plug

The OE plug was non-resistor AC heat range "4", which is AC 44, but AC no longer offers non-resistor plugs. AC heat range "5" is a better heat range for normal driving - more fowling resistant than heat range "4", so the best AC choice is R45.

NGK and Denso both offer non-resistor plugs equivalent to the AC 45, the B4 and W14-U respectively, so for a driver I recommend either of these plugs. This advice applies to ALL small blocks, regardless of horsepower rating.

Duke

[John D.]

Re: 67 HP 327 Spark Plug

Sal, The unltimate AC spark plug for your car is the AC46. Tough to find and rather pricey. One set should last you forever. If you foul out a 46 you have problems. Don't forget that we preach spark plus too much. Alsoimportant is to have the proper ignition coil to fire those plugs. John

[Salvatore I.]

Re: 67 HP 327 Spark Plug

Thanks everyone for the great feedback...

Duke,
Pardon my question, the NGK and Denso plugs are non-resisitors...can I use them without issue on a car with a radio?

Thanks......

[Duke W.]

Re: 67 HP 327 Spark Plug

Yes, as I said the OE plugs were non-resistor. GM did not start using resistor plugs until circa 1969.

Duke

[Salvatore I.]

Re: 67 HP 327 Spark Plug

Duke

Thanks for the great information...sorry, I missed the point you made on the OE plugs from GM, but I got it now...Thanks for the useful advice...

Sal

[Jim T.]

Re: 67 HP 327 Spark Plug

Sal I have always used Champion plugs in my 64 327/300, 68 327/350 and my 70 350/300. I used them for their extended tip feature. I have read of some that like the Autolite plugs. I installed Bosh plugs in my 85 several thousand miles ago and still getting good service. There is a lot to chose from.