L76_Cpar

I have a 65 L76. I read previous posts on the best spark plug. Seems like most like the R45 over the R43s. For an L76, do I need the R45 or R45S? I read a post the plugs sat a little lower in the high compression 63s and thus you wanted the standard R45. Is that the case for the 65?

Thanks in advance!!!!!!!!

Nowhere Man

What’s in there now? Is there something wrong that you need to change

Dan Hampton

The "S" refers to "extended tip". The non "S" plug (43,44,45) was the recommended plug for the L 76. The key regarding what heat range to employ is going to vary depending on a lot of factors, not the least of which is how you drive your car. The coloration of the plug will be the final arbiter on what plug is best for you.

Powershift

The "S" should be fine. But if you are very concerned........ pull them and check the gap after cranking over the engine with the starter a few times.

Larry

EDIT: My 1967 327/350 runs AC 45 and has no issues. I never required the "S" tip. My engine and yours should have similar pistons and heads (if your engine is original as mine is).

Dan Hampton

I remember the 45 S being used in 250/300 hp engines. Flat top pistons, so there was no problem with interference.

SWCDuke

All C2 327s were equipped with AC44 plugs. These were non-resistor types and over the years experienced owners found that the one heat range hotter AC45 was less prone to foul and is best of normal road driving including high speed freeway cruising. The AC 45 is no longer available, only the resistor type R45.

If you don't "have" to use AC plugs, like for NCRS judging, the NGK B4 and Denso W-14U are non-resistor types equivalent to the old AC45.

Duke

Powershift

Duke:

The AC 44 and AC 45 (and perhaps a few others) are available in reproduction. They appear to be well made and look identical to original. Probably some third party contracting with one of the manufacturers still used by AC to make the retro plugs. They are a bit pricey at about $60 a box of eight. With a bit of patience, original NOS can be purchased for the same money or perhaps even a bit less.

As you are aware, with the driving we do with these old cars and the unleaded gas many of us use, a new set of plugs will go 5-10 years. So the $$ are not so critical/important over this lifespan.

Larry

L76_Cpar

Thanks so much for your post. This is my first C2. This 65 car has sat covered in a climate control garage for much of the past 20 years so I am trying to go through it and get road-ready.

It idles rough so my first thought was plugs. I just pulled two plugs this morning and they are AC R45's. To my surprise, they were not bad. No oil or abnormal discoloration or wear on the first two so that gives me hope. I thought I would next check the timing. If it is the distributor, I will have some studying to do; I know nothing about points (I had a C3 with TI so never had to deal with points)....

Thanks again, I appreciate the thoughts...

Powershift

Points are easy............don't worry. Dwell should be 30 degrees +/- 2 degrees. Hopefully you have or can borrow a dwell meter. Once set they will go 12,000 to 20,000 miles. Just be sure they have a little dab of grease on the points rubbing block and on the points fiber cam follower.

With the 327/365 HP engine you will likely not be able to set initial timing before the engine will die. So you will have to rev it up (when warm) to 3500-4000 RPM so see when the mechanical advance quits advancing, and then set it to 36-38 degrees at that point. The vacuum can should be disconnected and the rubber vacuum hose plugged during this time. Note your RPM and what the mechanical advance is at idle............for future reference. Then reconnect the vac can and see if it advances the timing another 12-16 degrees. I believe the vac can should be a GM 236 which provides 16 degrees of vacuum advance at idle.

But regarding the rough idle. Your engine will idle a bit rough with the 30-30 cam. But if car sat up like you say, chances are the carb needs a cleaning and tune up.

Lastly, don't forget to check and reset the solid lifters.

Larry

Nowhere Man

Buy a old Snap On MT460 meter. this will help to trouble shoot why your engine is not running correct. this with a snap on timing gun along with a vacuum gauge you should be able to dial in your car without throwing parts at it in hopes of fixing it. This one on Ebay is grossly over priced though



https://www.ebay.com/itm/Vintage-Sna...kAAOSwHv1extpi

trarmour

Larry, 365 HP experts all agree to disable the vacuum advance on these engines for better run-ability and performance! . If you want to keep the original look you can JB weld the vacuum advance linkage inside the distributor or plug the rubber vacuum line with a nail and cut off the head or fill it with silicone. I prefer the JB weld or nail method as I wouldn't want the silicone to break down and get sucked in. Everyone knows vacuum advances were designed to increase mileage when cruising. That's all! On hard acceleration the timing goes to the timing set which on this engine is a 12 degrees advance and whatever the mechanical advance is advancing at the specific RPM. Also it should be noted that the vacuum advance needed for the 365 HP 327 is no longer available anywhere! If the currently available vacuum advances are installed on this engine it will drastically over advance the timing and cause the engine to "pop" at 30 or 40 mph. Crane used to make an adjustable vacuum advance which may work if the car owner is bent on keeping an active vacuum advance if they are still available. Hope this helps people who own a 365 horse 327. Tony

2KREDVert

Good luck starting the B4 threads in the SBC head. I bought a set of NGK B4s and am having major trouble getting the first thread to start in the heads. Anybody else have this problem?