I am interested in how
Moparts members would vote,
on what the chances would be of destroying a Magnum 360 V8 engine,
by repeatedly doing
wide open throttle accelerations
from 1000 rpm to 4000 rpm
on only 7 cylinders.

The wiring harness plug to the fuel injector electrical socket on the
'off' 8th cylinder would be disconnected
and the wire connector that would normally go to that injector would be plugged into a
'Noid Light' so that the PCM internal computer injector driver would not be harmed.

This would of course leave the 8th cylinder cold.

What are the chances
the cast iron block would distort or crack if
7 cylinder bores were enduring full heat for 30 seconds
and one cylinder sucking in and then exhausting just intake air?

Can a colder head gasket bore take having its neighbors fully hot ?

Since the hot coolant is still circulating through all passages in the engine this should somewhat even temperatures out, but certainly not completely.

Would the unbalanced vibration of the now V7 pulses be enough to cause unusually dangerous crankshaft vibrations?

Certainly there are vehicles with only 7 cylinders operating on the highways every day.

How many mechanics have encountered V8s that have operated for long periods with only 7 cylinders healthy?

Have any Moparts members
operated V8 engines for long periods
with only 7 cylinders firing?

Have any Moparts members
repeatedly taken 7 cylinders of a V8 to wide open throttle?
On a vehicle?
On a shaft Dyno?

The purpose of this is to find the real world
'power balance'
of each of the 8 cylinders.

What? are you that bored? I can tell you on a 440 one burned plug wire is worth about 4 tenths and a bunch of MPH. Not even sure if it was burned up at the start or not.

my guess is he wants to run the motor baseline w/all 8 cyls on a dyno, and then run it 8 times, each time with a different cyl disconnected to find out how much each cyl contributes to the overall power production, and to see if some make more power than others due to different factors, mainly intake and exhaust runner length variation would be my guess.

don't know the answer to your questions, though.

I think you might be ok.

don't know about the heat differences in the chambers possibly causing stresses on the head, or hurting the head gasket, but as far as only seeing impusles from 7 cylinders instead of 8...it shouldn't hurt anything...only 1 cylinder fires at a time anyway,

Or you could just run it and divide by 8.

Some folks have a lot of time on their hands!

Why do the full throttle?
I'm sure as heck aren't going to tell someone that asks such a question it's okay.
You will blame me for any issues now and for as long as you own the car.....

What the hell?

Enough people have a hard enough time getting thier cars to run on all 8 cyls. and this guy wants to run on 7?

I certainly would not blame anyone for giving their advice,
or sharing a past experience about an engine with one cylinder not working.

On the more general subject
of finding out
the 'health' of one cylinder
out of multiple cylinders on an engine,
is this the best way?

For alternatives,
there is a 'dynamic compression ratio test' that gives info on how one cylinder is.
There is a 'power balance test' where you cut out a cylinder at high idle speed and watch the amount of rpm drop... Ford actually has this built into their EEC-IV systems.
There is the much used cylinder leakage test using air pressure and two gauges.
There are the mountings of separate bungs for EGT and wide gauge AFR in each exhaust.

The above 'safe' tests have almost no chance of engine failure.

There are shaft dyno shops that bring an engine up to full throttle at some rpm, then momentarily short the ignition to one cylinder and watch the dyno for the torque drop. This is only done for the few seconds it takes for the reading on the dyno to be stable. This test has the chance of strong backfire in the exhaust.

What other ways can one test the health of one cylinder? (even at some risk)

Is it wrong to think of a
V8 as eight individual engines
worthy of being checked one by one?

You have listed acceptable and known tests. Why not use those instead of the
wide open throttle accelerations
you sugested?

All of the others are short, steady state and work.
What you are suggesting is under a hard load across a broad RPM range and under changing conditions. You will be inducing strong vibrations and harmonics at the very least.
Can/has it been done by accident? Sure. Should you do it as a test? I fail to see how it will give you any more information than doing the others.

maybe I got this
Bass-Akwards
and should instead be
cutting out 7 cylinders with Noid lights,
and running only one cylinder
at a time?

quote from retired Chrysler engineer Bob Scott:
-------
I worked for a year on the fuel injection program and during that time I was involved with the single cylinder testing I was telling you about. The single cylinder test stand was a 354 ci Chrysler hemi that had all but one piston, rod and valve set removed. The thinking at the time was it would be easier to work on one cylinder, make changes and get answers before making parts to test on a complete engine. The single cylinder engine had a means of advancing and retarding the camshaft while the engine was running and we could remove the cam lobes individually (exhaust and intake) and try different combinations and indexing on an almost infinite basis.

The intake was one perfectly straight tube that slid over another with close tolerance (like a trombone slide) so it could be lengthened and shortened to find the best possible length for the speed the engine was running. Intake runner tuning is the result of finding the point where the sonic resonance is maximized. When you put your hand in front of your bass stereo speaker you notice there is an air push. The same thing occurs in an engine. You can hear the induction resonance when you step on the gas with the air cleaner removed.

This intake resonance is very pronounced on a single cylinder engine, particularly when recorded and played back at a slower speed, which we used to do. It sounds like Bop, Bop, Bop. By the way, we also took high-speed films of the valve train and watched them in slower motion. All sorts of weird things that would never have been normally visible were discovered and fixed in this manner.

Someone, I think a brilliant engineer by the name of Bob Graham, deduced that if we tuned our intake runner to the point where the resonance was greatest, it would give the maximum push to the air and fuel when the intake valve opened at any given speed. The theory proved correct in the tests on the single cylinder and the results were reduced to a formula that was used from that day forward for ram manifolds on Chrysler engines. The runner as measured from the valve seat to the plenum (the open area where they normally meet under the carburetor,) can be determined by dividing 84,000 by the length of the runner = the speed the runner will work the best. An example is:

84000 (constant) = 5250 rpm
--------------
16 (runner length)

The formula worked with all camshaft designs tested, engine displacements, compression ratios, and bore and stroke combinations of the time.

An exhaust tuning formula was also developed on the single cylinder test stand. An example is:

205000 (constant) = 5256 rpm
39 (length of exhaust runner to collector)

On the exhaust tuning we found that we could flatten out the torque curve by adding length to the collector (the point where all the runners meet.) The collector on an engine with all cylinders operating was usually a tube measuring about 20% smaller than the total of all the exhaust runners.
------
end quote

from
http://www.allpar.com/history/memories/bob-scott.html

ahh dont do thet, I need the heads