[Edward Farrell]

What plugs are stock in a 67 catalina 400 2 BBL Auto NO Air?

[Edward Farrell]

What plugs are stock in a 67 catalina 400 2 BBL Auto NO Air?

[johnta1]

AC R45S I believe.

[starliner427]

AC R45S is correct.
We have a 67 Catalina 400 2 bbl with no air also. We installed an HEI distributor with AC rapid fire plugs. It really purrs now. The rapid fire plugs are expensive though. I used AC Rapid Fire part number 25171346 (#7). Most auto stores that carry AC parts either stock these plugs or can order them for you.

[Edward Farrell]

Starliner:
Did you get any more power from installing the HEI ignition and plugs? How about plug life? This engine only goes 5-6000 miles on a set. After that I cant get it much over 65MPH. And the plugs still look good. Been that way since the car was new.
Thanks for your reply and also Johnta1.
Ed

[starliner427]

We have the 400 2 BBL that back in 1967 was designed to run on regular gas. The engine is original with about 58,000 miles on it now and it has never been rebuilt.
The original old point distributor for the lower compression 400 has less total advance than most the other 400 engines of the same year. Also this engine has lower compression. The point distributor for the regular gas 400 has significantly less total advance than most HEI distributors. (One of the reasons HEI distributors have more total advance is because they were added to cars at the same time they added EGR valves which allowed more timing) So after installing the HEI distributor we now run premium 93 octane to utilize more timing. The fuel economy has improved to pay for the difference in the premium fuel. The seat of the pants power & smooth idle has really improved. No problem with plugs not lasting.
Regarding your plug life, I would bet your ignition system is too weak to fire the plugs as they wear. Do you recheck your point dwell after about 5000 miles? Set it to 28-30 degrees. The HEI distributor should cure this problem.
If you install an HEI distributor you should still change the plugs every 12,000 to 15,000 miles unless you go with a platinum tip spark plug.
If you install an HEI remember you need a full 12 volts to the distributor. I ran a wire directly from the ignition switch. Also you should gap your spark plugs around .045 with HEI. I purchased AC Delco spark plug wires for a 1977 Grand Prix 400 and they fit good.
Also, don't add any lead substitute to your gas. It adds deposits to the cylinders and promotes spark knocking. The valves will last without it.

[starliner427]

A cheap HEI distributor is available from Summit. Part number SUM-850007. I got mine on sale for $149.00 and the regular price is $189.00 If you buy this distributor, install the heavy advance springs that are included in the box. The springs that come on the distributor are too weak and allow the timing to advance too fast causing spark knock.
Another good one is the "ready to run" distributor from MSD.
I heard in California you only have 91 octane premium, so you may have spark knocking problems with the HEI distributors I recommended. So you may want to go to the "DRIVETRAIN STREET" board and ask about HEI distributor recommendations. I heard good things about a poster "Sun Tuned".
See this link: Sun Tuned thread

[Edward Farrell]

Starliner:
Thanks for the info. Sounds as though we have the same engine. I was reading an article in our local Pontiac club about an HEI system produced out here in California that several members swear by. I may give it a try. I could use a little more power. Thanks

Ed

[Phatcat]

What about using the HEI on a 400 with the high compresion heads? (code YD) Will I see any benefit. My car doesn't run well on regular but gets by on midgrade.

[Edward Farrell]

I dont remember, are R46 plugs a hotter or cooler plug? For some forgotten reason I substituted 46s in place of the 45s. I think because of the lower octane gas and the spark knock. And, while i am on the subject, has anyone used tetraethyl lead additive to add lead and octane to their gas. I have the original untouched motor in my 67 and am concerned about unleaded fuel. IE too low an octane and burning the valves. Comments???

[Phatcat]

Ed, Unless your car has been parked for the last 25 or so years, it's probably been running on unleaded for some time. I know my car has, and the motor has never been damaged, still running great after 37 years. Just takes around 5 minutes to get up to temp where it runs good. Although there's nothing like the smell of unburned premium coming out of the exhaust at a dollar a minute.