>I'm also curious as to how Jim responds to this question. One could also
>ask to compare the 351W with the 351C, which is, I believe, substantially
>the same question you pose. The only real difference between the 351W and
>the stroked shorter deck 289/302 block is the rod length to stroke ratio,
>which has been beat pretty much to death by this group a few months back.
There's also the main bearing size issue. The 351W has 3.00" main
bearings versus 2.75" for the Cleveland. Some say this makes a
meaningful difference in bearing surface speeds but, for most
applications, this is a non-issue. Around 400 hp or so, head gasket
sealing becomes a real problem with a stock 302 block due to flexing
in the block. The fix is a 351W or, if you have the bucks, an SVO A4
302 block. Be aware that the A4 block weighs a bunch more than a
standard 302 block.
>The taller 351W or 351C blocks allow much higher rod length to stroke
>ratios if you think this is important. Obviously, it creates a problem for
>installation in a Tiger, although not an insurmountable one. I believe that
>the biggest factor that affects the performance of the stroked motor versus
>the 351C would be the difference in the heads. The 4V heads for the 351C
>are essentially the Boss 302 heads which are huge. Of course, you could put
>these heads on the stroked Windsor motor with more or less the same
>results.
Also the intake manifolding. For many years, this was a problem
with the 351W. Even if you had a set of decent heads, the available
intakes were all low rise dual planes with small ports. It can also
be a problem on a fuel injected 5.0. At around 325 hp, the long runner
injection manifolds become a cork on a stock displacement 5.0. The
problem only gets worse on a stroked engine. Of course, there are
aftermarket alternatives now.
> But just putting these heads on the 289/302 block would still
>require some additional clearance in a Tiger. One might also ask about the
>weight differences between the stroked motor and the Cleveland block. I'm
>guessing the Cleveland is a little heavier than its 351 Windsor counterpart
>and certainly heavier than the shorter Windors, but there are even
>differences between various castings of the 289/302 short deck blocks;
>e.g., the Mexican 302s are a little heavier I've heard.
The following weights come from an early Ford SVO catalog and are
consistent with other published numbers. These numbers are for typical
engines. The dimensions include such things as air cleaners, oil filters,
water pump, fan, etc., but not bellhousings.
Engine Width Length Height Weight
289-302W 24.0 29.0 27.5 460
302 Boss 24.5 29.0 28.5 500
351W 25.0 29.0 29.0 525
351C 25.5 29.0 29.0 550
351M-400 26.0 29.0 29.0 575
These numbers are consistent with my experience. I weighed several sets
of heads and got the following weights:
50.0 lbs 289/302 - complete including rockers
56.5 lbs 351C 2bbl open chamber - bare
58.0 lbs 351C 2bbl open chamber - complete except for rockers
60.0 lbs 351C 4bbl closed chamber - bare
Adding 2 to 3 lbs for valvetrain weight to the 4bbl closed chamber heads,
yields 12 to 13 lbs more per head than a smallblock Windsor. For the
pair of heads, figure on 25 lbs extra for Cleveland heads. I expect a
Cleveland block to actually be a bit lighter, since it has a lower deck
and thinner cylinder walls. So a 351C should be about 25 lbs more than
a 351W (525 lbs vs 550 lbs). The 302 Boss weight seems high compared to
a 302W, especially considering its aluminum intake. It may have had
heavier exhaust manifolds.
If you really want to go wild on stroke, some 1973 351M/400 blocks use
the small block bellhousing bolt pattern (all the others use the 429/460
pattern). The 400 block gives you an extra inch of deck height over
a 351C (10.297" versus 9.206") or two inches over a 302 (8.2"). If you
want to retain the stock stroke, the stock rods are very long (6.580").
Dan Jones
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