BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

[Wayne M.]

Reading yesterday's thread on the potential 1969 L89 stamp pad, (link below) got me to thinking about the design change on the 842 heads that involved eliminating one of the end casting plugs. This occured (per Restorer article By Roger Gibson Vol 18 # 1) around June of 1969, at roughly the same time that the open chamber 6074 aluminum heads were introduced for the L88-only.

https://www.forums.ncrs.org/showthre...71852&uid=1679

So, my question is, which end did they eliminate ? Say, viewing the head from the valve cover (ie. top) side, if the head on the driver side had the plug on the front only, then an identical design head installed on the passenger side would show no plug in a photo of the stamp pad, as its plug would be facing the firewall.

So, which end plug is eliminated ?

[Warren F.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

That L71/L89 pad shows vin # 7315. Engine assembly of Nov 9th, 1968. The heads should have plugs on both ends during this time frame I believe.

[Wayne M.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

That L71/L89 pad shows vin # 7315. Engine assembly of Nov 9th, 1968. The heads should have plugs on both ends during this time frame I believe.

Warren, I totally agree, from what I've read in the literature. Were you the one who took the picture ? (and therefore can confirm there was no plug on that end of the head).

The reason I ask is as the picture was focused on the stamp pad, the rest is blurred due to depth of field. When I squinted, I could imagine seeing an out-of-focus plug with a square socket head there, but if you've seen it in person, then I'm obviously mistaken. Pic below shows one with plug very deep into head (ie. not even a full thread exposed) and this is what I thought I saw on the picture (shot at a vertical angle) in your other thread.

[Warren F.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

Wayne,

No I haven't seen that engine in person. I looked hard at that picture with magnification also. I see no defined edge for a plug, I do see the casting edge of an aluminum head without a tapped plug hole. Even at that photo angle the square hole for the pipe plug would be somewhat noticeable.

[Cecil L.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

Slightly off topic, but does anyone know of a source for this plug other than taking one from another head or block? I am missing one plug on one of the 858 heads on my 66 and currently have an ugly protruding squarehead pipe plug.

[Clem Z.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

Slightly off topic, but does anyone know of a source for this plug other than taking one from another head or block? I am missing one plug on one of the 858 heads on my 66 and currently have an ugly protruding squarehead pipe plug.

try a industrial electrical supply company they handle aluminum pipe plugs with a square insert hole in large sizes

[Cecil L.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

try a industrial electrical supply company they handle aluminum pipe plugs with a square insert hole in large sizes

Thanks for the tip, Clem. That's probably the only source I didn't try.

[Clem Z.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

Thanks for the tip, Clem. That's probably the only source I didn't try.

i have not bought any for about 15/20 years but that is where i got them

[Joe L.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

Thanks for the tip, Clem. That's probably the only source I didn't try.

Cecil-----


Try this:

http://www.mcmaster.com/#aluminum-pipe-fitting-plugs/=38uo96

I don't recall what the pipe size is, though. As a matter of fact, several months ago I purchased some of the GM plugs for cast iron big block heads, but I can't find them right now. I'm pretty sure the size of the aluminum plugs is the same as the cast iron version, though.

[Cecil L.]

Re: BB 842 Aluminum Heads, 2nd design: which end single casting plug ?

Cecil-----


Try this:

http://www.mcmaster.com/#aluminum-pipe-fitting-plugs/=38uo96

I don't recall what the pipe size is, though. As a matter of fact, several months ago I purchased some of the GM plugs for cast iron big block heads, but I can't find them right now. I'm pretty sure the size of the aluminum plugs is the same as the cast iron version, though.

Joe,
Thanks for the link. The cast iron plug is what I needed and I found one at McMaster and ordered it. Now I can remove the old ugly plug.