Spark Plug Recommendations? 67 327/350

[Brandon K.]

Hello all.....

Looking for the best spark plug to use on my L79. I have rebuilt using flat top pistons and comp cams extreme energy cam with specs similar to the original. Will probably go with AC plugs, but what heat range? Should I stay with stock plug or does the compression change mandate a different one? Thanks!!Brandon.

[Pete Wolff]

Re: Spark Plug Recommendations? 67 327/350

Brandon,

I am using AC R45's in my 1966 L79 (stock rebuild) and it performs flawlessly. I had 43's in previously and they had a tendancy to foul with sustained low speed driving.

[Pete Wolff]

Re: Spark Plug Recommendations? 67 327/350

Brandon,

I am using AC R45's in my 1966 L79 (stock rebuild) and it performs flawlessly. I had 43's in previously and they had a tendancy to foul with sustained low speed driving.

[Dave S.]

Re: Spark Plug Recommendations? 67 327/350

I would recommnd a 45 heat range for the "collector" car driving we all do. You could choose a 45, R45, 45S(extended tip), or an R45.

[Dave S.]

Re: Spark Plug Recommendations? 67 327/350

I would recommnd a 45 heat range for the "collector" car driving we all do. You could choose a 45, R45, 45S(extended tip), or an R45.

[Brandon K.]

Thanks Guys! Guess I'm getting 45R's... *NM*

[Brandon K.]

Thanks Guys! Guess I'm getting 45R's... *NM*

[Tom Merkel]

Re: Spark Plug Recommendations? 67 327/350

Dave - Understand you're thinking about or have recommended using AC45S (extended tip) in a '67 L-79? I can state without question they didn't work in mine. Fouled in approximately 100 miles. Had trouble getting it to idle properly, and it sounded far too 'throaty' to what I was used to hearing. I put AC44's in (per original spec), and they work to perfection. Smoothed out, idles, and a very even performance envelope.

Why did I even use extended tip? 'Cause at one point maybe a year ago,when buying plugs, the parts people didn't have AC44's in stock, and (unknowingly and uninformed) I said...sure. Gimme AC45S. Lessons learned.

I also used AC43 for a period, and to my way of thinking, they performed OK. Whether AC45's (hotter range) will suffice, I can't say, but would be interested in knowing any success folks may have.

Tom

[Tom Merkel]

Re: Spark Plug Recommendations? 67 327/350

Dave - Understand you're thinking about or have recommended using AC45S (extended tip) in a '67 L-79? I can state without question they didn't work in mine. Fouled in approximately 100 miles. Had trouble getting it to idle properly, and it sounded far too 'throaty' to what I was used to hearing. I put AC44's in (per original spec), and they work to perfection. Smoothed out, idles, and a very even performance envelope.

Why did I even use extended tip? 'Cause at one point maybe a year ago,when buying plugs, the parts people didn't have AC44's in stock, and (unknowingly and uninformed) I said...sure. Gimme AC45S. Lessons learned.

I also used AC43 for a period, and to my way of thinking, they performed OK. Whether AC45's (hotter range) will suffice, I can't say, but would be interested in knowing any success folks may have.

Tom

[Brandon K.]

Where do you get the 44's?

I heard they were out of production. Does the radio have more interference than with a resistor plug?

[Brandon K.]

Where do you get the 44's?

I heard they were out of production. Does the radio have more interference than with a resistor plug?

[Dave S.]

Re: Where do you get the 44's?

You can find them at swap meets, Corvettes Carlisle, Driveline Ads, Hemmings Ads, etc. Don't buy the newer style AC plugs as they are inferior to earlier plugs in the white, blue and red boxes. They are dated on the boxes and anything from the mid 70's and earlier is best. It takes a little work.

[Dave S.]

Re: Where do you get the 44's?

You can find them at swap meets, Corvettes Carlisle, Driveline Ads, Hemmings Ads, etc. Don't buy the newer style AC plugs as they are inferior to earlier plugs in the white, blue and red boxes. They are dated on the boxes and anything from the mid 70's and earlier is best. It takes a little work.

[Duke W.]

Re: Where do you get the 44's?

If you want a quality non-resistor you can readily obtain the NGK B4 or Denso W14-U. These are equivalent to the AC45, and this slightly hotter heat range works better for normal driving, that the OEM AC heat range "4" (AC44).

The AC44s fouled out pretty readily on my '63 SHP engine on the street, and I used the colder AC43s with good success for race track hot happing sessions.

Duke

[Duke W.]

Re: Where do you get the 44's?

If you want a quality non-resistor you can readily obtain the NGK B4 or Denso W14-U. These are equivalent to the AC45, and this slightly hotter heat range works better for normal driving, that the OEM AC heat range "4" (AC44).

The AC44s fouled out pretty readily on my '63 SHP engine on the street, and I used the colder AC43s with good success for race track hot happing sessions.

Duke