I would not even consider being afraid of going .030 over. Now we do have a .060 4 bolt main block that i was skeptical about using:dodgy:
Here is some info borrowed from another site:
> Just how far can a 351c block be bored to? Some say .030 is it. Others
> say .060 is.
Only your sonic tester knows for sure. Some blocks are marginal at
standard bore, most will go 0.030" and I know of one 0.060" that's at
432 rear wheel horsepower but that's the exception rather than the rule.
Hardblocking certainly helps.
> As far as strength is concerned, what exactly is the difference between
> 2-bolt main blocks & 4-bolt blocks?
The usual failure mode is cylinder wall cracking but sometimes the saddles
will crack. I wouldn't worry about 4 bolt mains until I had a 1/2 fill of
hardblock. 4 bolt mains may help with main cap fretting, though.
> Also, are there blocks known to have thicker cylinders than others (aside
> from Ford racing pieces, that is.
After Ford quit producing the 351C, the Australians continued on with
production with a series of 351C blocks. You'll see them for sale but beware
there are multiple Aussie blocks. Only a few are the 4-bolt main, thick
wall, variety. A batch of maybe three hundred XE-192540 blocks were cast
specifically for racing back before the Motorsport blocks were available.
These are the thick race blocks. A real XE-192540 blocks weighs
considerably more than a standard Cleveland block, has thicker cylinder
walls, unsculpted pan rails, and beefier 4 bolt main caps. I've had one
of the 2 bolt Aussie blue blocks and currently have one of the NASCAR XE
4 bolt main blocks. The 2 bolt Aussie blue block looks much like a standard
U.S. 2 bolt block and weighs about the same on my bathroom scale. If you
place it (or a U.S. block) side-by-side with an XE block, their is no
comparision. The XE block is noticeably different.
The Cleveland V8 was introduced to Australia as a 351C in late 1969 (as a
1970 model) for the XW Falcon GT series. These engines were imported from
the Cleveland, Ohio plant in the United States. In 1972, a 302 Cleveland
was introduced in Australia (never exported to the U.S.) in the XA Falcon
series. These blocks were also from Cleveland, Ohio but the engines were
presumably assembled in Australia using a 3" de-stroked crank. As in the
U.S., those blocks could be 2 or 4 bolt main. In 1974, Ford discontinued
production of the 351C in the United States but Australia continued
producing them until 1982. Those blocks were manufactured in Australia.
The early Australian blocks were referred to as blue blocks (painted Ford
blue) and are similar to U.S 2 bolt main. In 1976, electronic ignition was
introduced and a subtle revision to the distributor hole was made. These
blocks were still blue block though. In 1979, the black blocks were
introduced and remained the standard block until production ceased at the
end of 1982. All of these blocks had the smaller distributor hole but
also reputed to have thicker bores but not nearly as thick as the real XE
race blocks.
I've been informed that there may have been black blocks that were
produced with the XE casting number. I've not confirmed this as a fact
but it's easy enough to check for. As long as the block has the casting
number, 4 bolt mains (beefier than U.S. versions), and unsculpted pan
rails, it's a good one. Besides being heavier, the XE caps are reputed to
be made of higher nodular iron. There may be Siamese bore and non-Siamese
bore versions but I've not been able to confirm this. It's always a good
idea to inspect for core shift by having the block sonic tested.
A number of late model Pantera and Longchamp owners have inspected there
Aussie blocks. Some had the different diameter distributor hole and all
had minor casting differences with U.S. blocks. Some had D2AE-CA casting
numbers, which are also shared with U.S. blocks. The casting differences
include bulges between the freeze plugs and the pain rails and an oval
Ford logo to the left of the oil pressure sender. U.S. blocks may have a
smaller (1") poorly defined oval there but the Aussie block oval is larger
(1.5" to 2") and very well defined.
Kip (formerly of the Pantera Performance Center in Colorado) bought a
batch of Aussie 2 bolt main blocks, and sonic tested them all. He says
their wall thickness was about the same as U.S. 2 bolt blocks and some
did not pass sonic test. These may have all been blue blocks. I also
had one of these blocks and it weighed about the same as a U.S. 2 bolt
main block. My XE block is quite a bit heavier and exhibits all the
characteristics mentioned previously. Kip has had several XE 4 bolt main
blocks in the shop and said they were all great (no core shift problems)
and he's bored them out as much as 0.187" over (to fit a sleeve) and
never gone through a wall. Some sources have said that there were XE
blocks that did not pass core shift inspection and were passed on to
passenger vehicles so there may be some XE blocks out there with core
shift problems. Always a good idea to sonic check and visually check
for casting uniformity. This goes for aftermarket race blocks too.
So the bottom line is there are Aussie blocks and then there are Aussie
blocks. Summarizing, blocks used in Australia could be:
1. Blocks imported from the U.S. before Australian-sourced blocks were
available. Could be either 2 or 4 bolt mains.
2. "Blue blocks" (painted Ford blue). These were the earliest Australian 2
bolt main castings. Probably not any thicker than comparable U.S. blocks.
Later vesions had a small diameter distributor hole (see below).
3. "Black blocks". These were later Australian 2 bolt main castings that
were introduced. All were equipped with electronic distributors. The
distributor hole (at the bottom) is smaller, so U.S. and earlier Aussie
distributors won't fit without modification. The distributor hole is the
same except for the hole in the block that holds the very bottom of the
distributor. The diameter difference is small, like the difference between
a 12mm wrench and 1/2" wrench (0.5mm). Supposedly a thicker casting than
the "blue blocks" but not a huge difference like the XE blocks.
4. 4 bolt main non-Siamese bore. A special casting for U.S. racing.
Only a few hundred made. This is the one with the straight pan rails.
The real NASCAR blocks will have an XE casting number prefix (e.g. XE
192540), thick, non-contoured main bearing webs, one inch thick block
skirt (pan rail), heavier, high nodular iron four bolt main caps, and
usually 0.165 inch minimum thickness cylinder walls. However, even
XE blocks may have thin spots. I sold my XE block to Jon Kaase for his
PHR Engine Masters Competition entry and he sonic checked it. He reported
it was thin a couple of spots. That really didn't bother him though as
he was most interested in the beefier pan ran area.
5. Same as number 4 but with Siamese bores. Use a coat hangar snaked in
through the core plug holes to test. If it's Siamese, the cylinder walls
will touch and you won't be able to push it through the adjacent cylinders.
There could be others. I've heard of Aussie truck blocks but I don't know
if they are any different than passenger car blocks. After the U.S. 351C
supply dried up, DeTomaso sourced the engines from Australia. They were
basically truck motors with open chamber 2V heads. I've heard nothing
special claimed about the blocks. Aussie 302C and 351C blocks interchange.
I've also heard that towards the end of the production run, there were
variations in the blocks like 4 bolt main black blocks that had sculpted
mains. They may just have been using up left over stock or tooling.
If it's an Aussie block, there should *not* be a "CF" Cleveland Foundry
marking. Check the casting indications on the rear face, lifter galley,
inside the timing cover, for a "CF" or any other bits that may indicate
it's origin.
My Aussie 2 bolt block had no Cleveland Foundry marks but had a D2AE-CA
casting number, the same as one of my 4 bolt main U.S. blocks. It did have
rows of XXX's and YYY's in the lifter valley but they don't appear to mean
anything relevent to the country of origin or wall thickness. Bare, clean,
with main caps and a standard bore, my Aussie blue block weighed in at 172
lbs on a bathroom scale. A 0.030" over U.S. block weighed in at 170 lbs.
The XE block weighs more. I'd guess an extra 20 lbs or so but I have not
had it on the scale yet. I'm 400+ miles away from it at the moment so can't
just run out and weigh it.
For reference, here are some U.S. casting numbers scammed from the 'net.
Year Type Casting #
==== ====== =========
1970 2-Bolt D0AE-A,D0AE-C,D0AE-E,D0AE-G,D0AE-J,D0AE-L D0AZ-D
1971 2-Bolt D0AE-A,D0AE-C,D0AE-E,D0AE-G,D0AE-J,D0AE-L D0AZ-D
1971 2-Bolt (CJ) D2AE-CA D1ZZ-A
1971 4-Bolt (HO) D0AE-B,D0AE-D,D0AE-F,D0AE-H ????-?
1971 4-Bolt (CJ) D2AE-CA D3ZZ-A
1971 4-Bolt (Boss) D1ZE-A,D1ZE-B D1ZZ-D
1972 2-Bolt D2AE-DA DOAZ-D
1972 2-Bolt (CJ) D2AE-CA D1ZZ-A
1972 4-Bolt (HO) D2AE-EA D1ZZ-D
1972 4-Bolt (CJ) D2AE-CA D3ZZ-A
1973 2-Bolt D2AE-DA DOAZ-D
1973 2-Bolt (CJ) D2AE-CA D1ZZ-A
1974 4-Bolt (CJ) D2AE-CA D3ZZ-A
1974 2-Bolt D2AE-DA DOAZ-D
1974 2-Bolt (CJ) D2AE-CA D1ZZ-A
1974 4-Bolt (CJ) D2AE-CA D3ZZ-A
HO = High Output
CJ = Cobra Jet
Boss = Boss 351
Dan Jones
