[AMC-list] (no subject)

[Nick ALFANO <71amx@xxxxxxxxxxxxx>]

Hi Jeff,

The different compression in 71 was actually piston and head combo changes from 10.2:1, 9.5:1 and then late in the year was the same as 72 which I recall being 8.5:1.  Once the head changed in 71 from the 51cc chamber to 58cc, even though the part number changes from 71 thru 73, the chamber volume remained the same 58cc.  In 74, they change was to the rocker design going from a screw in stud style rocker to a bridge over design.  

To my knowledge, AMC never made a production car 401 engine with more than 10.2:1 compression.  Most of the spec books out there only show the 9.5:1 engine numbers with 330hp which is 10hp less than the 70 390 claims.  I suspect the 10.2:1 401 engine had more hp than that but I haven't found any number  It was probably in the 350hp range.

I have the high compression piston part number somewhere.  I will see if I can dig it up.

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

Message: 1
Date: Sun, 24 May 2009 15:57:23 -0400
From: "Thomas, Jeff" <jeff.thomas@xxxxxxxx>
Subject: Re: [AMC-list] Last 401
To: amc-list@xxxxxxxxxxxx
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    <2BEA03C6137B454CB50F2E92146D05CA1C22D218@xxxxxxxxxxxxxxxxxxxxx>
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Jim,
High compression should be associated with the heads. The '71 heads are
generally broken down by "early" which is Sept 70 to about January 71
based on a casting number stamped into the heads. These high compression
heads should be stamped 3196291. I think they were 11.5:1 compression.
These heads are a holdover from the 1970 390 block heads so they were
made for 2 model years (70 and 71). 

In late January or early February 1971, the heads were downgraded to
10.5:1 compression and have a casting number of 3212993. These are also
pretty good heads from a compression standpoint. I think they were only
made in 1971. By 1972 the heads had been downgraded again to 9.5:1
compression. These heads should be stamped 3213948. On my 71 Jav AMX I
run 3216090 which are the '73 and '74 401 block heads. These are reduced
again in compression to 8.5:1. Plenty of meat for around town driving
and turnpike cruising on the weekends. 

PS: Do you still have the beautiful white 71 Javelin SST ? I have 2
articles on your car from years ago. Nice ...

Jeffrey Thomas
ORL FL  

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