AC 45 or AC 43 plugs on a 365hp ?

[David K.]

I'm running AC 45 sparks on my 65' 365hp. I have heard that AC 43 runs cooler and could be a preferable application for my motor. I'm currently having overheating issues (goes up to 210 degrees) after 6-7 miles of city driving. Entire car is factory stock (Holley 2818 carb and 180 degree thermostat). Changed my coolant with Zerex-05 a couple of hundred miles ago & I'm running with Rotella 15-40 oil. Thanks in advance.

[Joe L.]

Re: AC 45 or AC 43 plugs on a 365hp ?

I'm running AC 45 sparks on my 65' 365hp. I have heard that AC 43 runs cooler and could be a preferable application for my motor. I'm currently having overheating issues (goes up to 210 degrees) after 6-7 miles of city driving. Entire car is factory stock (Holley 2818 carb and 180 degree thermostat). Changed my coolant with Zerex-05 a couple of hundred miles ago & I'm running with Rotella 15-40 oil. Thanks in advance.

David-------


The heat range of a spark plug has little, if anything, to do with engine operating temperature. It has much more to do with fouling propensity of the plug. For a street-driven L-76 I think an AC 44 or 45 would be about right.

[David K.]

Re: AC 45 or AC 43 plugs on a 365hp ?

Thank you Joe; I will stick with the AC45 plugs. I run the car from stop sign to stop sign; in the back streets and VERY rarely take it for a long run on the highway. I have the original 2818 carb getting back from a rebuild by Bob Kunz next week - and will swap the unit on board right now. I know that I have to check my timing etc. before anything else.
Regards from Montreal; David

[Bob W.]

Re: AC 45 or AC 43 plugs on a 365hp ?

David In the last two months or so there have been a number of post about engine temperature. So look at the back pages. Also some talk about a 66-67 ac air dam to lower the temperature. This block the air from going over the radiator between the rad and hood. DR rebuild has this part #1274506 paragon #13760k both are in the $30.00 range. Hope this helps.

Bob

[George W.]

Re: AC 45 or AC 43 plugs on a 365hp ?

David,

I run AC-45 in my '65 395; it runs cool at 180 to 190 on a hot day with a 180 degree stadt. Shoot the top and bottom radiator hoses and if
there is not a difference of 25 degrees cooler at bottom hose start looking at radiator issues; good luck; it should run cool.

George

[Gene T.]

Re: AC 45 or AC 43 plugs on a 365hp ?

How do I contact Bob Kunz? I have the original 2818 carb that I need to have rebuilt.

[John D.]

Re: AC 45 or AC 43 plugs on a 365hp ?

I have AC R45S (extended tip) in my 67 350hp for years.

[Philip A.]

Re: AC 45 or AC 43 plugs on a 365hp ?

I'm running AC 45 sparks on my 65' 365hp. I have heard that AC 43 runs cooler and could be a preferable application for my motor. I'm currently having overheating issues (goes up to 210 degrees) after 6-7 miles of city driving. Entire car is factory stock (Holley 2818 carb and 180 degree thermostat). Changed my coolant with Zerex-05 a couple of hundred miles ago & I'm running with Rotella 15-40 oil. Thanks in advance.

David
Your question is about spark plugs but your issue is overheating. Lots of good advice regarding this issue in the archives. Recommend going through these to systematically go through the issue. Something as simple as ignition timing or a defective radiator cap could cause your problem. As an FYI, it is the water in the system that does the actual cooling.
Phil

[Joe L.]

Re: AC 45 or AC 43 plugs on a 365hp ?

How do I contact Bob Kunz? I have the original 2818 carb that I need to have rebuilt.

Gene------


Very easy. Bob is a registered user on this board. So, you can contact him via e-mail or private mail.