In a message dated 97-09-08 01:21:54 EDT, laifman@flash.net (Steve Laifman)
writes:
<< You read the source, but neglect the details. The "devil" is in the
details. Look at the pictures. You can see the head water/steam hole
differences. Non of the sources you've mentioned go thru the "details"
of interchangeablity. If you don't believe the pictures, and you don't
believe tbe "urban legends", then check with your real experts in "hot
rodding" your car. I am absolutely positive that you will find a few
surprises. Ford did not move those holes without reason (blown head
gasket problems). The gaskets did not include passage ways without
reason. The knowledgeable speed shops do not perform extra machining
without reason.
I do not intend to send ^^^flames^^^, but if you do not know, for sure,
the reasons, do not recommend your solution. It could lead others
astray, and I am sure that is not your intention.
I am NOT claiming I hold the "answer", just the "question". Is it wise
to ignore the Ford engineering changes without understanding their
rationale?
I respect your authority to make your own decisons, for your own use.
Before you recommend others follow your path, please explain Ford's
engineering change to the 351W heads, gaskets AND BLOCK, and why they
should be disregarded.
Respectfully, If not in agreeement,
Steve
--
Steve Laifman < One first kiss, >
B9472289 < one first love, and >
< one first win, is all >
< you get in this life. >
Steve,
I checked out the pictures of both the heads as well as pictures of the
block. By 'steam hole' if you are referring to the oblong slot/hole in the
head that is located above the combustion chamber on the intake side, that
hole moves around and changes shape all through the evolution of the heads.
It lines up with the small hole above the bore on the later engines (early
engines had 3 small holes above the bore);
Ford Muscle Parts as well as the old Carrol Shelby supertuning book
recommends tapping and plugging THAT hole in order to modify coolant
circulation on engines running at higher revs.
I talked to one of the guys at Summit Racing, and he didn't know about boring
any extra holes. He sounded positive about that.
I have another guy that builds Ford engines for the NASCAR circuit that I
will check with, and I will let you know what he recommends.
I am curious about the holes, as I have run my '69 small chamber (DOOE
casting), ported and polished with GT40 valves, for several years on both 289
and 302 blocks with no problems. Having said that, I am on the hunt, like
ALL Tiger owners for that magic bullet to defeat overheating when stopped in
traffic.
If you have concrete info, I want it.......no kidding.
As to why Ford changed the 351 heads, we turn to 'How to Rebuild Your
Small-Block Ford, Page 35 "351W- Even though they are unique, 351W cylidr
heads are basically the same as all other small block Ford heads. Starting
in 1969, comb chamber volumn is 60.4 cc. 1.84" and 1.54" valves with .3410
stems are used. Four extra intake manifold bolts are accomodated by a corner
cast into each of the 2 intake manifold water passages. This changed the
water passage shape from a rectangle to an L shape requiring a different
intake manfold gasket. In 75 the water passages became common with the 302s
and the extra manifold bolts were dropped. 351W heads are internally
manifolded for air injection from 75 on. 351W heads became common with 302
heads in 77 with the phase in of stamped rocker arms through 78. Combustion
chamber volumn was increased to 69cc.
Thats the head changes..........
Now for the 351W Block changes.....
Both the Muscle Parts and the How to Rebuild books show that the only
recorded changes to the block was in 74 when the deck height was changed from
9.480" to 9.503"
There is no mention of any changes to the water passages.
As I am sure that you are aware, there are many different head gasket
manufacturers out there, and their gaskets are mostly just a little
different. Currently, I am running the SCE solid copper gaskets .090 thick,
because I am running the 289 HiPo rods in a 302 block in order to get a
little better rod angularity and hence a little more torque.
Again, I say that if ANYONE out there knows of extra holes needed in thse
heads, and you can document your source, let me know.
In closing, I must not be a 90's kind of 'thenthative' guy, 'cause I don't
consider a disagreement a flame!!!!!!! :)
Best Regards,
Ray
|