Overview
We left off in Part
One with a completed short block, already stabbed with
a healthy Crane soid roller cam which will help reach
our goal of 400 HPs. What remains of course is the
top end. This is where the power is made, and thus proper
component matching is critical. In this article we'll
go through the head and intake selection and assembly.
Heads
World Windsor Sr. feature
200cc intake ports. |
As we mentioned last month,
we will be running the World Products Windsor Sr. heads.
We choose these because we got them cheap (used), with
relatively few have a few miles on them. In fact, they
are under $800 new, and so long as you don't mind the
weight of iron, they flow as good as most 'out of the
box' aluminum heads. The heads will be a substantial improvment
over stock castings, in that they have a redesigned combustion
chamber, modified spark plug placement for better burn,
and of couse the larger 2.02" intake and 1.60" exhaust
valves to increase flow. The World Sr. comes with massive
200cc intake runners which, if ported, can support displacements
much larger than 302 cid.
Head Clean Up and Prep
Small block Ford heads are have notoriously restrictive
exhaust ports and bowls, and that is where most professional
porters spend their efforts; especially on stock castings.
Although the World heads would work great out of the box,
we noticed quite a bit of casting flash that could easily
be removed with a grinding stone. This sort of "clean
up" work is cheap and easy horsepower.
There are many stages of porting heads, ranging from the
basic clean up to the complete re-shaping of the ports.
If you don't know what you are doing, taking off too much
material in the wrong places can easily cost you power
and even ruin the head. Therefore we suggest you leave
a full-on port job to the pro's.
All we performed on the iron World Sr. heads was to smooth
out some casting ridges and irregularities as shown below.
On our cast iron World Windsor Sr. heads there were
sharp edges and casting material around the valve
guide bosses. We used our sanding rolls to smooth
this out and blend the area around the guides. This
will reduce airflow turbulence. |
Looking down the intake port of our our of the box
World Sr. heads, you can clearly see the surface
irregularities on the walls, and the large casting
ridge running down the center of the floor. A little
time and effort spent smoothing out these imperfections
with a die grinder or Dremel tool can substantially
improve flow and performance. |
We had the heads milled to clean up the mating surface,
but also to gain some compression. The 64cc head
was milled down to 59.5cc, in order to yeild about
9.4:1 compression ratio. We then checked the combustion
chamber volume. See Measuring Combustion Chamber
Volume in the Fundamentals section of the Tech Department
for a detailed tutorial on this process. |
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(Head Assembly) |
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