AMC 401 cylinder boring

[Nick ALFANO <71amx@xxxxxxxxxxxxx>]

Kevin,

Typically, .040 overbore is fine on a 401 but it
really is dependent on your particular block.  Some
blocks had thinner walls than others do to a shift in
the core when they were cast.  Best thing to do is
have the machine shop sonic test the block to see how
much thickness you have.  I have seen blocks that ran
hot at .030 over and others that we bored much more
run fine on 100 degree days.  In fact last year, we
built a stoker 401 that was bored .085 and it never
got over 180 degrees.  The cylinder walls were so
thick, that we could have went up to .115 over and
still been within spec.

Since they messed it up, make then do the test to make
sure otherwise, you might get it done just to find out
that it runs hot all the time.

Nick Alfano
Alfano Performance
Kenosha, WI. 53142
262-942-8271 

From: KCHAP@xxxxxxxxxxxxxx=20
To: eddiestakes@xxxxxxxxxxxxxxxxxxxx=20
Sent: Thursday, March 02, 2006 9:54 AM
Subject: AMC 401 cylinder boring


Mr.Stakes,   Hello, my name is Kevin Chap.  I own a
1978 Jeep J-10 Pick 
=
up with an AMC 401.  I recently had the engine totally
rebuilt which =
went horribly wrong.  The mechanic forgot to install
the valley pan and 
=
PCV baffle on the intake.  With nothing blocking the
oil from the PCV =
valve, the engine sucked three quarts of oil in a day
and a half of =
driving.  To make a long story short, The cylinder
walls were scarred =
pretty bad.  The mechanic started the project boring
the cylinders 
.030" =
over.  He then bored an additional .010" to repair the
damage.  I've =
heard many opinions on what is a safe bore for the 401
without =
overheating and was wondering if .040" over is pushing
it.  I don't 
race =
the truck and it is pretty much an in town weekend
driver.  I have some 
=
performance mods including Edelbrock intake, carb, and
headers, MSD =
distributor, ignition box and coil.  (no oiling
modifications).  Any =
advice would be appreciated.  In a big Chevy town,
it's good talking to 
=
an AMC gu!
 y. =20
=20
Thanks again,                                         
                  
=
                                                      
                  
=
           Kevin Chap=20


kchap@xxxxxxxxxxxxxx