MWood24020@aol.com wrote:
> Now I am confused, I was certain that the 260/289/302 motors all had the same
> deck height. When I installed my late-model, roller cam 302 in my Tiger, the
> exhaust ports were exactly in the same position as the replaced 260, which,
> unless the dimensions of the heads differs, would lead to the assumption that
> the deck heights were equal. I know the 351W deck height is significantly
> higher.
> The 289 block/302 crank combo is pretty common among those building
> motors.With a .030 overbore it results in a 306 cid motor. Also, the early
> 289 block is desireable for a stroker build, as the casting in the bottom end
> has more "beef" than the late model 302s.
> I am not sure the 302 crank/260 block combo wouldn't work, if rod and rod
> journal dimensions etc. are the same.
> Mike
Mike,
You are correct about the deck height being the same in the 221/260/289/302
blocks
at 8.206 in., BUT only through '72, based on Monroe's table on page 31. After
that he lists 8.229 in. on '73-76, back to 8.206 on 77-78 (end of my earlier
version book's table.) The Deck Height, in this period practically disappears
to
0.0005, rather than 0.034. The Compression Height, likewise, changes (distance
from pin to top of piston) goes from 1.60 in 221/289/ and '68-'72 302, to 1.605
in
302 73-76 (not much difference) to 1.616 for 77-78. Someone may have a newer
release of this book, and maybe these were typo's and maybe the table gets
up-to-date. But that's what it says.
In addition, it specifically says you can't put a 302 crank into a 221, even
though the 'numbers add up', because the bottom of the 221 piston will hit the
connecting rods. Not applicable to us, of course, but it shows that there are
lots of considerations.
A similar situation exists in the 289/302 area. Even with the same bores and
piston compression heights, the 289 piston skirts are longer, so you've got to
use
302 pistons with a 302 crank in a 289 block. This makes a "302" out of a "289",
which is the object, of course. Since '78 Ford's "Service Pistons" for 289 2V
and
'68-'72 302's are interchangeable.
HOWEVER, watch out for BALANCE. I think you are getting into the 28 oz. to 50
oz. external balance change, with attendant flywheel, ring gear, starter,
counterweight, pulley issues. A NEW 302 bare block is about $260, with Roller
Cam
capability.
I have been told that early 302's had some problems with the piston skirt
lengths,
and the end of the bore casting at the bottom. Not sure of the details, but
warned to buy the 302 blocks. etc., that came out AFTER the HiPo 302's were
released. Anyone with details?
Bottom line to ORIGINAL question:
So, it looks like, with a lot of ifs here, that a 302 crank in a 260 will give a
272.5 CID engine, increase compression ratio, and may be little change necessary
IF any 302' cranks were 28 oz.
Steve
--
Steve Laifman < Find out what is most >
B9472289 < important in your life >
< and don't let it get away!>
_/_/_/_/_/_/_/
_/ _/_/_/ _/_/_/ _/
_/ _/ _/ _/ _/ _/ _/_/_/_/
_/ _/ _/ _/ _/ _/ _/
_/_/_/_/_/__/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
_/
_/_/_/
|