Got this from a gent down under:
"Hi Greg, Well my personal experience was with the original Buick 3.5 V8
casting. I don't know where you are, but I see the Servicesoft company is
based in the states. So the following makes and models may not mean a lot to
you, but you should be able to get the parts imported or what ever.
Concerning the Buick/Rover 3.5 block they don't recommend boring it out past
0.020" (20 thou). I went for coma and bored it out 0.063" (63 thou) with no
problems.
I used 179 Holden pistons as the compression height was spot on. They are a
flat top piston but sit down lower in the bore. The standard Buick/Rover
piston has a higher compression height, but is a "bowl in piston" type, so
they lower the comp that way. Using the Holden piston's was good in a couple
of other areas, Cheap, readily available and because they sat down lower in
the bore you can put a big bump stick in it without having to worry about
the valves hitting the pistons. Also the Holden pins are smaller so I was
able to convert them from a press fit to fully floaters and fit bushes to
the rods - blessed!
Right that's me, this is you.
You've got a 4.4 out of a P76 ehh? Were did you get that in the states?
OK ! This is what you will need.
8 x ACL P/N# 3623B or 3625 Sleeves.
8 x ACL P/N# RY3000 060 piston set. They come in a set of 6 so you will
have to buy 2 more with pins, rings etc. Go for the Duralite slugs, there
better and chrome molly rings.
Right, because I am an Automotive Machinist by trade and had all the gear at
my disposal and years of experience around me to call on, it was pretty
simple. I used a AMC overhead boring bar which uses the sump face as the
index. The sump face is used as the index for all engines as is the rocker
cover face for the heads.
Whoever you get to do the work for you, make sure they have an overhead bar,
period. If they have a portable bar and index off the head face - expect
problems, it's a no no. Go somewhere else.
OK they will know what to do, bore the sleeves off center, collapse them,
remove them.
Next: index up the bar to the bore centers and bore out the parent alloy to
take the "B" sleeves. The B sleeves are thicker in the wall and provide more
strength. They will step the bottoms to they can't fall into the crankcase
and get wound up with all those reciprocating bits down there uck. Only
kidding it wont happen. The heads will stop them coming out the top. This is
why this has to done on an overhead bar as the y need to go in perpendicular
to the crankshaft in both the X & Y planes so the that the slug will travel
up and down perfectly square to the mains. If you don't understand this let
me know and I'll go into more detail. If the machine shop can't explain it
to you leave as fast as you can, you are talking to Aliens!
Once the sleeves are fitted. Ohh! nearly forgot, the main caps should be
fitted and torqued up while all this is going on. We don't want anything to
distort afterwards do we?
Now a good idea is to fit a set of head plates to the head surface for the
same reason, no distortion, then just bore the sleeves to suit and hone of
course.
They might have to machine a bit off the bottom of the skirts so they don't
fowl the crank, but they will know all this.
You will need to work out the compression ratio and either machine the tops
of the pistons or open up the chambers.
Fully balance the motor and all the things that hang off the crank, goes
without saying.
Result 4899cc or 298.8 CID that's some mumbo. You can stroke them up to 5.2
litre but that involves more dosh. The way I suggested is pretty common and
cheap."
Good Luck.
Regards Mike Rammelt.
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