Clarification on '69 Camaro L89 head design

[LS6 RAT]

I have noticed on a couple of '69 Camaro L78/L89 optioned engines that they seem to use a head that does not have the pipe threaded plug on the end of the head.
In the Corvette world, no '68 or '69 L71/L89 optioned engine had an aluminum head without those threaded plugs.
What's the story with these heads? Thanks.

[427king]

The plug on the end is dependant upon build date of the car. [ QUOTE ]
In the Corvette world, no '68 or '69 L71/L89 optioned engine had an aluminum head without those threaded plugs.


[/ QUOTE ] I have both 842s and 074s dated in early 69 that dont have plugs,so i am not sure that statement is correct.

[LS6 RAT]

427king,

That's what I'm confused about. Every L-71/L89 Corvette optioned engine uses the closed chambered '842 head, all have the threaded plug. This head of course is also used on the majority of the 116 '69 L-88 Corvettes. I believe the last 44 L-88's were equipped with the 2nd design head, which of course is the '074 developed for the ZL-1 and used on all of the 188 1971 LS6's, this head of course did not have the plugs.
In an article written by Roger Gibson on aluminum heads, published in the Corvette Restorer magazine a few years ago, it shows the different aluminum heads used on Corvettes from '67 thru '71. Never was any mention of the '842 head manufactured without the threaded plugs. I'm just wanting to get educated on this.

[427king]

[ QUOTE ]
This head of course is also used on the majority of the 116 '69 L-88 Corvettes. I believe the last 44 L-88's were equipped with the 2nd design head, which of course is the '074 developed for the ZL-1 and used on all of the 188 1971 LS6's, this head of course did not have the plugs

[/ QUOTE ] The 074 heads came out around Oct 1968, i have May 69 842s w no plugs.

[nuch_ss396]

Hold on a second here. The '842 heads started with two plugs
( one in each end ). Later '69 production '842 heads
had only one plug in just one end. I wasn't aware of any
'842 heads with no plugs. Does anyone have a set of these?
I'm betting they might be service dates if they do exist.

Steve

[Hotrodpaul]

Here are pics of my 69 Camaro SS L-89 engine with one 842 head 3/69 and the other 5/69. No plugs in either end.

http://i3.photobucket.com/albums/y86/Hotrodpaul86/DSCN3622.jpg

http://i3.photobucket.com/albums/y86/Hotrodpaul86/DSCN3645.jpg

http://i3.photobucket.com/albums/y86/Hotrodpaul86/DSCN3647.jpg

Paul

[LS6 RAT]

427king & Hotrodpaul,

Thank you for clearing this up. I certainly learned something! Is the exhaust valve face diameter 1.84"?

[69 Post Sedan]

[ QUOTE ]
Hold on a second here. The '842 heads started with two plugs
( one in each end ). Later '69 production '842 heads
had only one plug in just one end. I wasn't aware of any
'842 heads with no plugs. Does anyone have a set of these?
I'm betting they might be service dates if they do exist.

Steve

[/ QUOTE ]

Here are some pictures of my 842's that are dated 8/68.

[69 Post Sedan]

Another picture.