I've been building 500's for 7 years now, and though I don'tknow
everything, I do have quite a bit of education in motor design.
Actually I've been putting one together right before I got online.
As far as putting in main cap reinforments, I see a couple of
problems. There isn't enough room in the cap it convert to a "4
bolt" main. I think you would have to "cap" the cap with custom
machined peice, and I think that would do more harm than good.
Drilling into the webbing is BAD! Also unlike a lot of engines I've
seen the caps are machined to slide into the webbing with incredible
tolerances, this in turn transfering the vast majority of all force
except absolute vert. into the webbing without stressing the cap
bolts. The crank itself will prob. take anything you can through at
it but rpm. If you've pulled the pan and looked at it you would see
that the bearings are giant, oil passages average, and crank throws
thick, making a huge peice of FORGED steel. Cadillac wasn't cutting
corners. The metal they used would rival anything ever made(short
of aircraft using moly, and a few industrial engines, I've never
found a better alloyed crank) and the dimensions should be able to
handle 1000 ft/lbs+ as long as you don't hit the resonance tone.
This means treat it like a big block, don't rev it ablove 5000/5500,
MAYBE 6500 if you have it extremely well balanced. These motors get
a lot of bad publicity for bad rods, in reality its the rod bolts
that go. Even those that know this usually agrevate it by putting
in the hardest bolts they can get. Hard bolts BREAK, anealed bolts
stretch slowly, devleoping increased tolerances, and in extreme
cases "knock." Remember that it's the exhaust stroke that breaks
rod bolts, they have to stop the piston, and F=MV^2, so again if you
keep the rpms the 5000 like you said you plan the stcokers will take
more than you think, again caddy didn't scrimp. I take that back,
there rocker assembly is junk. You need to change the springs
atleased , should change the rockers to. They can hardly take the
As far as block wear, the block can be polished and bored to 500,000
miles easy. I've pulled apart motors with 100,000 mile on them that
have measured out on the tight side of factory specs. Again this
comes from the alloys, more nickle than you would probably believe
(just don't tell the scrap mongers, they aren't making any more of
these you know).
If you are running a lot of boost and plan on driving this thing
around (pump gas would nice/aka cheap) I'd recomend running the
early pistons with the late heads resulting in about 7/1 static
compression, allowing a good share of boost and still staying in a
reasonable final comression range for 92 octane, but resulting in
and effective increase in air/fuel being burned. Basically trick it
into thinking its bigger than it is.
For trans, I believe all gm EXCEPT chevy will fit, but the TH400
behind it is as good as they come. A caddy fleetwood 75 weight is
6,000 lbs empty, throw in the 9 passengers they were made for, and
the 525 ft/lbs of torque, a lead foot, and 100,000 miles these could
easily do, and it doesn't take and engineer to tell you they are
tough. If you must change it go to www.cad500parts.com they will
have all you need. I've got parts from them since 2000, when they
were cadillac motorsport development, and they've always treated me
As far as differences is the block, unless you get a pre-500 472,
there are the same. I've heard you have to do some notching in
those blocks if you want to put in a 500 crank, but I've never run
into one. I'm sure you also know that if you just put early heads
on late pistons (depending on the cam you run you might have to
relieve the pistons) you can get into the range of 13/1 compression
on the cheap without turbos.
I'd be happy to answer any questions you have, but i just opened
this e-mail to repond, please email at Justinknwh@...
As a last note I would upgrade the rockers/cam, three angle the
valves, port a set of late heads, put them on an early block, HEI
the ignition, boost it good and run the TH400 with a shift kit/tall
rear gears, and hope the tires are speed rated, and the suspension
can handle well up to the speed the car leaves the ground. good luck
and drive well.
--- In Cadillac_Performance_Association@yahoogroups.com
> I am no expert, but I do have the 500 mated to a FWD turbo 400 in
> motorhome. I believe that everything is shared with the 455 Olds
> Toronado setup, leading me to believe you could use any GM
> olds/buick/chevy/cad trans.
> --- In
> Cadillac_Performance_Association@yahoogroups.com, "timiacobucci"
> <timordog@h...> wrote:
> > Hi everybody, my name is Tim Iacobucci and this is my first post
> > this board. I haven't been interested in the big cad engines for
> > that long and I wish I knew about them sooner as I really like
> > research things thoroughly and I have a good knowledge base on
> > engine I've worked on so far but this one. 460 being my first
> > love, sorry to and ford haters out there but I figure the ford
> > chevy thing doesn't really extend to Cadillac and there are
> > probably a good amount of you here that enjoy romping bbc's as
> > much as the 460 crew with our "boat anchors". I haven't
> > had to long to comb the archives here but I can see there are
> > definitely people here with the 500 knowledge I'm looking for.
> > First I guess I should describe my project. I'm setting up 500
> > with 2 grand national tubros carbed to put in an 85 monte carlo.
> > From other message boards I've read a stock 500 makes a g car go
> > 11's, which I can believe if the torque numbers I hear about are
> > realistic. I've heard older closed chamber pre emissions headed
> > 500's were rated at 550 ft. lbs., how true have you all found
> > this to be? I ask because it leads into my next question which
> > durability which I directly relate to torque production (within
> > stock rev range). I plan to keep it under 5 grand as I hear that
> > a good practical limit to keep these engines comfortable but how
> > much torque production do you think this engine can tolerate
> > it begins breaking stuff. I plan to upgrade head and main studs
> > will go with somebody's forged rods if there are no cheaper
> > strength interchange rods from another engine? I also plan to o-
> > the block and weld up some sort of custom steel girdle/side bolt
> > device and accommodating pan. I want to use as much boost as I
> > make without destroying the engine, what are the practical
> > the stock engine, and what levels do you think are possible
> > correcting any weak points? I was told that the rods/rods bolts
> > would be the first to snap under big torque. If this is
> > and if I can control cap walk how much abuse do you believe the
> > stock crank can endure? Are there any other cranks in between
> > and full out custom billet? How strong are the mains and what
> > of meat is there for like maybe splayed 4th additions? Has
> > ever blown a cyl wall? I plan to keep the overbore as small as
> > possible for cyl wall strength, I've heard these blocks can be
> > very hard and have very good wear characteristics, is there a
> > of cleaning up and using stock bore? Would some hardblock help
> > all, I don't want to do too much as I want to drive it on the
> > street and would like to keep as much water as I can.
> > My next big question is interchange. I plan on probably using a
> > venture probably 4500 but depending on the durability of the
> > just possibly a 5600. Does anyone even know a source for these,
> > lbs. is harsh but not intolerable if it can endure massive
> > loads that would makeup for its weight. So how can I attach this
> > trans, what flywheels/ clutches will work with this engine? Does
> > share any other gm bellhousing like maybe an olds and if I were
> > go auto with a th400 is the stock behind a 500 that's rwd a
> > core to build on, and what cars have these and which are 425?
> > these any different from other 400's and do any other flexplates
> > or starters interchange? Are some blocks better than others if I
> > get pre 73 heads elsewhere or is there a way to check for a good
> > block other than opening it up? How much does mileage generally
> > affect these engines, should I look for a high mile seasoned
> > or a low wear low mileage one? What other parts if any
> > with any other gm engines? And rods or pistons, I know no
> > crankshafts interchange but are there any year or type cranks
> > are know to be stronger? Any other little bits or parts, fuel
> > oil pump/filter, water pump or accessories/brackets?
> > I know that's a whole lot of questions but I'm real eager for
> > info, I plan to get the MTS book, any other recommended caddy
> > reading? Any and all answers, opinions or speculation is very
> > appreciated and I am very thankful for any helpful
> > you may share.