Correct Spark Plugs for 1968 SUper Bee 383

[bobfake]

Hi all,

The Super Bee is running good, but not great...I've put on a new distributor cap, rotor, wires and set the timing. It runs "OK", but not like I feel it should. I pulled one of the plugs and it is clean and gapped properly, but...it's a Champion RV17YC. When I look this up at the parts store, it states this is not the correct plug for my 383.

The Service Manual states a Champion N14Y (which nowadays is an RN14YC), which tells me that the RV17YC plugs are 3 steps hotter than factory.

Could this be causing it to run a bit rough? I'm going to get the Champion RN14YC plugs and replace them all or would you recommend another brand?


Thanks!!
Bob

 

[toolmanmike]

Hi all,

The Super Bee is running good, but not great...I've put on a new distributor cap, rotor, wires and set the timing. It runs "OK", but not like I feel it should. I pulled one of the plugs and it is clean and gapped properly, but...it's a Champion RV17YC. When I look this up at the parts store, it states this is not the correct plug for my 383.

The Service Manual states a Champion N14Y (which nowadays is an RN14YC), which tells me that the RV17YC plugs are 3 steps hotter than factory.

Could this be causing it to run a bit rough? I'm going to get the Champion RN14YC plugs and replace them all or would you recommend another brand?


Thanks!!
Bob

View attachment 1422527

Go back to the 14's.

 

[dadsbee]

Not sure why anyone would put 17's in a 383. J12Ys are probably what it really needs. Nothing wrong with Champions. My last set ran (and was still running) mine from 1988 to 2016... albeit was parked for 12 of those but started right up and idled clean Fall of 2015.

 

[RemCharger]

Somethings amiss. Why do you have a taper seat plug in your picture..
What heads do you have..

 

[pnora]

What heads? If stock that is the wrong plug.

 

[bobfake]

What heads? If stock that is the wrong plug.

Bone stock to the best of my knowledge...

I suppose that could be part of my problem...tapered seat will not seal properly as the correct plug with gasket would...agree??

Interestingly...the Champion website show only J12YC and RJ12YC as correct plugs for my Super Bee. Looks like that's actually the correct plug and is 5 steps cooler than the RV17YC and has the gasket seal...

 

[dadsbee]

Yep.. all you can buy off the shelf these days J or RJ for radio suppression and also yes why I suggested 12Y's for yours.

Who put those tapered plugs in there...

 

[RemCharger]

If you're 383 is fully stock with original heads...
I would recommend NGK XR5.
NGK is the most widely used original equipment spark plug in the automotive world due to many reasons with the top one that we're concerned with being unmatched Quality.

 

[bobfake]

Yep.. all you can buy off the shelf these days J or RJ for radio suppression and also yes why I suggested 12Y's for yours.

Who put those tapered plugs in there...

I purchased the car out of CT in September 2022. I have $13,000 worth of receipts the prior owner gave me with the car and the shop he used for nearly all of the work in CT did a full tuneup (based on receipts), so I assume they installed the RV14YC's...

 

[pnora]

What heads do you have for sure? Might be later heads that take a taper seat. If the shop that did the tune is on the ball they used the right plugs. Maybe you should pull a valve cover and get a casting number. Then look at the plugs head seats.

 

[khryslerkid]

Plugs with a ring or crush gasket. See the recess...

Taypered plug. Note the bump.

 

[Dave6T4]

I agree that Champion RJ12YC would be the correct plug with original "906" heads. If these tend to soot up with infrequent short cruises, you could always go with a slightly hotter RJ14YC plug.

 

[bobfake]

Looks like tapered? This is number 5 cylinder…

if these are not “906” heads, what would they be and how do I determine the right plug?

 

[pnora]

Looks like tapered? This is number 5 cylinder…

if these are not “906” heads, what would they be and how do I determine the right plug?
View attachment 1422619

So they are not original 1968 906 heads. Most likely 452 76-78 vintage.

 

[RemCharger]

Looks like tapered? This is number 5 cylinder…

if these are not “906” heads, what would they be and how do I determine the right plug?
View attachment 1422619

You pull a valve cover and check the casting #.
Kinda does look like a taper...

 

[bobfake]

Yeah...looks like it's a taper after doing some more research...I'm not going to pull the valve cover because I just went through and put new ones on and got my valve cover leaks resolved. I don't want to have to redo that.

Last question - the Champion RV17YC is still apparently a lot hotter than the stock RJ12YC that was called for. Should I go for a 12 heat range tapered plug versus the 17? Also - the Champion website shows the RV17YC is for a 225CI engine...

 

[pnora]

I would go with the RV12YC the 17 range might of been used for a fouling problem.

 

[RemCharger]

It crosses over to a UR5 if you want to go that route

 

[Geoff 2]

Not sure what 'running good, but not great' actually means......
Could mean, rough idle......
Could mean, I thought a 383 would have better acceleration.......
Etc.

A too hot plug might cause pre-ignition. If you are not getting this, then I would keep the current plugs.

 

[Some Car Guy]

I can’t imagine a stock engine needing hotter plugs. What do you know about the build? I think at this point you need to pull the cover and see just what you have.

the NGKs 5s are what I use. They cover a wide heat range so that isn’t a concern if you happen to need hotter than stock.