Impalas.net banner

1 - 9 of 9 Posts

·
Registered
Joined
·
38 Posts
Discussion Starter #1
Hi folks!

I have a 1967 Impala 283 sbc factory original and while doing some research about what spark plugs to choose when would them need a replacement, I found out there are two different seat type (gasket and tapered). Besides other specs, how I know which one should I have on the engine? Have to take one spark plug out and use it as reference for new one? Are both type compatible in some cases?

Regards to all!

Luís
 

·
Registered
Joined
·
270 Posts
The two seat types don't interchange. Well, it's not a good idea anyway. The best thing to do is pull a plug so you know 100% what you have.
 

·
Registered
Joined
·
38 Posts
Discussion Starter #3
Thanks for your reply, AK99.
In the meantime, I've just pull out one spark plug and is a tapered type. But a quick search in the web shows mostly spark plug type for sbc 283 are gasket, e.g. AC44. Is there a chance that were two different heads, one for each type? Or mine has been modified/replaced?
 

·
Super Moderator
Joined
·
2,915 Posts
Your car came with spark plugs with gaskets. Over the years its not uncommon for heads to be changed. Someone may have installed later model heads on it. The only way to know is to run the numbers on the heads under the valve covers.
 

·
Super Moderator
Joined
·
13,089 Posts
You may have a 350 out of a pick-up truck that just says 283 on it as all Chebbies rook arike. Like has been stated you had the big 13/16 hex washered plugs originally with PowerPack heads (it was possible to have fuelie heads but unlikely on a 283 in an Impala). If you have accessory mounting holes in the heads it is a later model gasketless (aka Tapered seat also called a Peanut Plug) spark plug head.

A lot of miles on these cars means a lot have replacement motors out of a bone yard as being cheaper than rebuilding the original motor.

Big Dave
 

·
Registered
Joined
·
141 Posts
Pull a valve cover & get the casting number off of the cylinder heads... Look up the number of the cylinder heads and get new plugs for that vehicle(s). Or as a second alternative, cross what you have pulled out back to an AC plug and away you go... Chevy's always seem to run better on AC plugs & Mopar's on Champions.
 

·
Super Moderator
Joined
·
2,915 Posts
Reminds me of the time a guy drove a car over to have me put a new set of AC spark plugs in. After installing them it wouldn't start. I changed them to Autolite and it fired right up. Have never used another AC plug in over 30 years.
 

·
Registered
Joined
·
123 Posts
The only problem I had with AC was when I was hitting 5 0f 8 before rebuild. I and just went to AC 45 R, a little hotter and the car stereo stopped the hi pitch buzz along with the engine speed thru the speakers. Those were the days!!
 
1 - 9 of 9 Posts
Top