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Lot's of issues chasing horsepower with a 260 project. The 260's smaller
bore restricts valve size, valve shrouding occurs with any valve bigger than
1.85". The stock pistons barely produced 8.5:1 compression even with the
small-chamber heads, shaving the heads enough to get real compression brings
squish zones down to a few thousands and screws up flame front propagation,
so there is only so much that can be gained, plus the castings can't support
the port sizes needed for modern induction. Sure you can spin one to 8 grand
but it won't make much power because it won't breath, but I suppose a four
valve per cylinder head would cure that!
Once you decide to spend the $900 for custom pistons then doors open. A
3.40" stroke crank brings 313 cubic inches, and better breathing heads, a
full roller cam and valve train, and modern intakes all help build torque.
Still not a revver but a good street engine.
Of course you have to ask yourself WHY? I mean, who is going to know which
block is in your car? Who cares? Well some folks do, since I have built a
couple 260's for them. To them, bragging rights that it's the original
engine are important. Others just prefer stashing the old 260 under the
bench and building something more modern. That's what I did with both my
Tigers, both sport 5-bolt 289 based engines.
I just finished another 5-bolt 331 engine (all Ford Motorsport components
this time) and have two more 5-bolt blocks left, then I think I'm done.
Bugz
PS If you REALLY want a challenge I ran across a first-year 221 SBF.
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link=3D"#0563C1" vlink=3D"#954F72"><div class=3DWordSection1><p =
class=3DMsoNormal>Lot’s of issues chasing horsepower with a 260 =
project. The 260’s smaller bore restricts valve size, valve =
shrouding occurs with any valve bigger than 1.85”. The stock =
pistons barely produced 8.5:1 compression even with the small-chamber =
heads, shaving the heads enough to get real compression brings squish =
zones down to a few thousands and screws up flame front propagation, so =
there is only so much that can be gained, plus the castings can’t =
support the port sizes needed for modern induction. Sure you can spin =
one to 8 grand but it won’t make much power because it won’t =
breath, but I suppose a four valve per cylinder head would cure =
that!<o:p></o:p></p><p class=3DMsoNormal><o:p> </o:p></p><p =
class=3DMsoNormal>Once you decide to spend the $900 for custom pistons =
then doors open. A 3.40” stroke crank brings 313 cubic inches, and =
better breathing heads, a full roller cam and valve train, and modern =
intakes all help build torque. Still not a revver but a good street =
engine.<o:p></o:p></p><p class=3DMsoNormal><o:p> </o:p></p><p =
class=3DMsoNormal>Of course you have to ask yourself WHY? I mean, who is =
going to know which block is in your car? Who cares? Well some folks do, =
since I have built a couple 260’s for them. To them, bragging =
rights that it’s the original engine are important. Others =
just prefer stashing the old 260 under the bench and building something =
more modern. That’s what I did with both my Tigers, both sport =
5-bolt 289 based engines.<o:p></o:p></p><p =
class=3DMsoNormal><o:p> </o:p></p><p class=3DMsoNormal>I just =
finished another 5-bolt 331 engine (all Ford Motorsport components this =
time) and have two more 5-bolt blocks left, then I think I’m done. =
<o:p></o:p></p><p class=3DMsoNormal><o:p> </o:p></p><p =
class=3DMsoNormal>Bugz<o:p></o:p></p><p class=3DMsoNormal>PS If you =
REALLY want a challenge I ran across a first-year 221 =
SBF…<o:p></o:p></p></div></body></html>
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