Bob Palmer wrote:
> The good Mr. Laifman has offered the following: "The scientific explanation
> is that your mechanic is full of sh--. The 260 block has the same OD of the
> cylinder to the water jacket, but a smaller bore, so the walls are THICKER
> than a 289. The factory (FORD) recommendations on boring are a maximum or
> 0.060 inches on the 260, and 0.040 inches on the 289."
Actually, Bob, if you drew the conclusion that I was claiming the 260's
(and I DO mean the 3 freeze plug models ONLY as on the Tiger, not the
earlier 221 over sized 2 freeze plug), then I mistated my intent. The
REAL intent is to state that the 260, 3 freeze plug model had a thicker
wall than the 289, but not the same OD to the outside of the wall. I
totally agree that it would be very unusual for core shifting to be so
negligible that a bore to the 289 4" would leave a satisfactory wall.
I was only emphasising, for the purpose of the inquiry about 260 boring,
that the FACTORY, and the ROOTES MANUAL (see
http://www.TigersUnited.com) specifically state the overbore limits to
be .060 for the 260, and .040 for the 289. THAT IS ALL. And Doug should
NOT listen to his "expert mechanic's" incorrect data. I thorough
examination of the block for miscast originals with out-of-tolerance
walls is never a bad idea, though.
> There are two distinct schools of thought on this, those that think Steve is
> the one "...full of sh--", and those who don't. Amongst the many standing in
> opposition to Steve is the following from an "official" Ford FAQ's Website:
>
> "Many 289/302 parts fit earlier 221/260 engines (which had smaller bores).
> They also has less metal around the bores, so you can't overbore to come up
> with a 289."
Never believed you could, either. Just that the 260's had a thicker wall
than the 289's, not the same outside diameter. I probably made a wrong
statement about the absolute wall thickness ("The scientific explanation
is that your mechanic is full of sh--. The
260 block has the same OD of the cylinder to the water jacket," should
have read:
"The 260 block has a thicker cylinder wall than the 289, allowing for
more meat for a bore"
I stand corrected on this error of typing too fast. The conclusions,
however, stand as specified in the manual. I apologize for the
mis-statement on the wall OD, but not the conclusions or recommendations.
Steve
--
____________________________
Steve Laifman
Editor
<http://www.TigersUnited.com>
|