452 heads,spark plugs

[casey henson]

I am not sure but unless I am seeing this wrong it looks like I might need taper seat plugs instead of gasket plugs. It has gasket plugs in it now but it looks like the washers have been crushed into a tapered seat shape.

 

[WileE]

I believe you have motorhome engine heads, which if I recall, use the tapered style plugs.

 

[Gus chiggins]

heads that use the tapered plugs. RV12Y, I think that's the plugs. I have those heads on my 383.

 

[ckessel]

Those may be the heads off of a 440-3 motorhome chassis. If so, a #25 Autolite or equivalent in another brand is your choice.

 

[zyzzyx]

Dang, I didn't know that!

 

[khryslerkid]

Spark plug Help

 

[Sinitro]

Those may be the heads off of a 440-3 motorhome chassis. If so, a #25 Autolite or equivalent in another brand is your choice.

Correcto...
These heads require a different spark plug, that's why they have the little nub raised area..

Just my $0.02...

 

[Gus chiggins]

Correcto...
These heads require a different spark plug, that's why they have the little nub raised area..

Just my $0.02...

View attachment 1378826

Yep, i found that out when i got spark plugs.

 

[moparmarks]

Pretty sure all 76-78 452 heads use these plugs. The several sets that I've had/have do.

 

[PRHeads]

Most of the 452’s I have come across have been machined to use gasketed plugs.
I’ve probably only had a couple sets here that used the tapered seat plugs.

The head in this pic obviously uses tapered seat plugs, since there is no spot faced counter bore for the gasket to seat against.
And there is a well defined tapered seat(under the paint).

 

[PRHeads]

In this pic you can make out the spot face, but it’s pretty filled in with crud.

The threads look to have some cross threads or some other unhappiness going on.
I’d probably try a thread chaser to clean them up

 

[PRHeads]

Here’s a head I have in the shop......

Pic of the spark plug hole clearly shows spot face and clean area where the gasket has been sealing.
Also notice there is no tapered seating area.

13/16” hex gasketed plug fits with plenty of room to spare.