Re: [AMC-list] AMC-list Digest, Vol 46, Issue 28

[Nick ALFANO <71amx@xxxxxxxxxxxxx>]

Sorry Frank but you are 1 year off.  The first full year for the bridge over 
rockers on the larger V8 heads was 1974.  The 73 year castings for the most part 
were screw in studs.  That is not to say that when production change over 
started, there were not some late 73 360s or 401s that got the 74 head with the 
bridge set up.  The 304s on the other hand got the bridge overs earlier than the 
360-401 head.  That maybe why you are seeing something in a 73 manual with a 
bridge over rocker

Nick
 Alfano Performance
4849-76 st.
Kenosha, WI. 53142
262-308-1302
262-942-8271 after 6pm central and weekends 

Message: 1
Date: Mon, 28 Jan 2013 19:22:23 -0500
From: Frank Swygert <farna@xxxxxxxxxxx>
To: amc-list@xxxxxxxxxxxx
Subject: Re: [AMC-list] First year for AMC bridged rockers?
Message-ID: <5107163F.70509@xxxxxxxxxxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Date: Sun, 27 Jan 2013 14:30:30 -0600
From: "Eddie Stakes"<eddiestakes@xxxxxxxxxxxxxxxxxxxx>

A customer asked me what year did AMC start using bridged rockers. I could
not give him a window. Always though 74 but know that these first appeared
in 1973, just not sure how early. A 401V8 I have out of a 73 AMX has a valve
cover tag of 612Z05 which is December 5th, 1973 401. The heads are casting
3220602 E and have bridged rockers, the flexplate is dated 7 73 (July 1973)
and engine never been apart. Waterpump 3215719 1 never replaced so as I look
at this, I am trying to establish a timeline, or window as to when AMC first
started using bridged rockers on AMC heads. This is earlier than I thought.
Ideas?
================================================

1973 model year it is! All the 1973 model year engines should have bridged 
rockers, which means they should have started engine production around August 
1972.

In 1974 the six at least went back to shaft rockers for most of the model year. 
There was a patent dispute filed by Buick over the bridged rockers. The 74 TSM 
shows shaft rockers for the six, but still shows bridged for the V-8. Might be a 
slight difference in the bridge design, might just be an editing error in the 
TSM. I don't know for sure if early 74 V-8s went back to single stud rockers or 
not, maybe one of the V-8 guys will know. I can tell you that the shaft rockers 
were dropped late in the 74 model year and they went back to bridged before the 
model year was up, but I don't know for sure when. For 1975 everything was back 
to bridged rockers as the patent dispute was resolved. I have no idea how -- 
can't say if AMC just won, paid Buick, or there was some other agreement (maybe 
a patent license swap -- that's happened before -- Buick may have got permission 
to use something AMC had patented in exchange).

-- 
Frank Swygert
Editor - American Motors Cars Magazine
www.amc-mag.com
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