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Preparing the "Cannonball Run" Plymouth Duster 340

BY RICHARD EHRENBERG. Copyright © 1989 Richard Ehrenberg. Used by permission. First printed in Mopar Action


... Or how I restored and tweaked a rusted, decomposed muscle car in six easy weeks.

was around Christmas 1988, I think, that I first heard it mentioned.
Frank Pogoda, our fast-thinking staff writer, came up with it. We (High
Performance Mopar,
part of CSK Publications) should field an
entry or two in Brock Yates' "One Lap of America," his quasi-legal
successor to the infamous "Cannonball Run."

For those of you who've never heard of the One Lap,
it's a seven-day rally of about 8500 miles that roughly follows the
perimeter of these continental states. In theory, it's run at legal
speeds, keeping the police happy. In reality, running legal speeds for
24 hours a day leaves little time for gas stops, food, taking a whizz
and, mainly, stacking some ZZZs. What starts out looking legal, then,
quickly escalates into a high speed run.

It was our intrepid editor, Steve Collison, who first suggested the car we should use: my primo 440 6-Pack Plymouth Road Runner, vintage 1969. The memo came across my desk in late January and read
something like, "I want your bod, bud." Assuming he meant the car and
not yours truly, I said no way, Jose. First off, the car's just too
good. Then, there's the little matter of the huge hood scoop, which
sucks in birds, small planes and LOTS of rainwater. Mainly, though, if
the outcome were flip, roll, crash and burn, where would I get another
one? They just don't build 'em like that anymore.

That out of the way, we got down to some serious negotiating. Don
Keefe, our resident Pontiac proponent, had two suggestions: one, build
a GTO-style wagon; or two, borrow a prototype of Pontiac's latest
"TransSport" plastic minivan. Two images immediately popped into my
cranium. First, since I'm the only staffer with a reasonably equipped
shop, I'd be the one to build the wagon, and I don't know anything
about Pontiacs. Second, driving 8,500 miles in an underpowered
family-oriented people mover seemed like it would be less than fun.

Another few weeks of negotiating transpired, putting us into
mid-February. Once I had nixed the 'Runner, I offered up my latest
winter beater, a 1974 Plymouth Duster 360. This suggestion received a rather cool reception by everyone.

Undaunted, I continued to extoll its virtues. It's a real muscle
car. It even looks like a muscle car, sort of. It's got decent brakes
and suspension. It's a Space Duster, with a fold-down rear seat for
sleeping. Why not?

Don, Frank and Steve told me why not: It's a clapped-out rust
bucket. If they waved at me when I drove by, the quarter panels waved
back. The seats looked like something off skid row, what with the
springs pushing clear through the foam. The car was three different
shades of blue, a result of numerous fender benders while in the hands
of the original owner, a little old man from Connecticut. In short, the
car would need a complete restoration to be presentable and roadworthy.

I didn't see it that way. It ran great, staying even with new
'Stangs, a result of the second owner's engine swap: a mildly tweaked
1971 340 sat where the smog 360
had once resided. The 5.0 ponies would typically pull a three-car
holeshot on me, a result of the 2.94 open rear. Once the Duster hooked,
though, they'd pull no more. Then when they had to grab second, my 340
was just coming into the power band and I'd pull even. My 1-2 automatic
shift usually coincided with their 2-3 grab. Once in second gear, I'd
usually pull a car length or so, which I had no trouble holding.
Definitely not a slug.

The mill miraculously burned zero oil, started on the first twist of
the key, and idled reasonably well. It was perfectly healthy, or so I
thought. The suspension seemed fine, as did the binders. So it needed a
little bodywork, seats and carpet. Our good friend Mike Levandowski of
County Auto Reconditioning in Peekskill, New York, volunteered his
services for the external restoration. Auto Custom Carpets of Anniston,
Alabama, agreed to cover our rusty floor pan, and Marty Beckenbach of
Legendary Auto Interiors in Macedon, New York, said he had the patterns
and fabric for the seats, no sweat.

See? I could have it restored in a few weeks. Yeah, I know the rally
starts in Long Beach, California, in early April, and it was already
late February, but what the hell, it's gonna be a quickie restoration.

So the die was cast. It would be a three-man crew of crazies, Don,
Frank and myself, loaded into my Rust Duster for 8500 miles of
partying. What a blast this is gonna be.

I started by planning the bodywork. Sherman and Associates of
Roseville, Michigan, sent us a pair of patch panels for the quarters,
on which Mike got right to work. Unfortunately, once the lower quarters
were cut off, we discovered that the inner quarters were about the
thickness of store-brand bathroom tissue. Mike had to make a pair of
inners from scratch (actually from an old K-car door), which set us
back a few days. Not to worry, this'll be a cinch.

Mike sent out the bumpers for rechroming, and the rechromers
promptly "misplaced" one of 'em for a week or so, using up a bit more
time. Still, I was relaxed. I proved my coolness by killing another few
days upgrading what were already excellent brakes. EIS Brake Parts
supplied us with a complete set of top-of-the-line brake goodies,
including new 11.87-inch rotors and 11x2.5-inch rear drums. If that
won't stop a 3400-pound car, what will?

Jack Koziol of Jack's Auto Parts saw to it that his supplier,
Classic Car Graphics, came up with a primo set of exact repro stripes
for our ride, which we had professionally installed at Mike's body shop.

The car was looking great!

Then a light bulb went off in my head. Eighty-five hundred miles of
high-rev cruising on no-lead in a car with a 1971 motor equals fried
exhaust valve seats. A hastily placed call to Frank Biscoglio of
F&C Cylinder Heads in Mount Vernon, New York, confirmed our fears.
Chrysler didn't begin induction-hardening the valve seats until 1973,
leaving us vulnerable. Damn. Gonna need to yank the heads and get them
down to Frank for some hard seats. Frank agreed, luckily, to push aside
mounds of work and give us top priority, as well as letting us poke
around with our camera, resulting in a great how-to article.

That night I yanked the heads, gave the cylinder walls a quick
glance, but I wasn't too concerned. Remember, this motor had burned no

After I got the heads back from Frank, I climbed in the engine
compartment and gave the holes a close look. Holy cow! Number 4
cylinder is "deviated," looking something like a ribbed condom. It's
now March 10, and the company that agreed to schlep this sled to the
West Coast for us wants the car by the 29th. Omigod.

I sat around for a few days, undecided about what to do. Expert
opinion was divided 50-50, going something like: "It didn't burn any
oil or make noise, so if it ain't broke, don't fix it," or "You're
going around the country with that motor? Hah!" Not usually one to have
trouble making decisions, I was nonetheless in a complete tither. Do I
fish or cut bait?

Then the hammer really dropped. The first "driver's bulletin" from
the Cannonball maniacs showed up. First, the length of this insanity
was up near 10,000 miles, and it would include several "timed
competitive events," including Solo 11 autocrosses, track events
(Sebring, Atlanta, Independence) and even hill climbs, including Pike's

That was it. I had to build a motor, and fast. Real fast.

A search of my basement, which is stocked (literally) to the rafters
with speed and restoration goodies, turned up a 1968 340 bare block
that I had bought at a swap meet some years back. It was supposedly
CK10'ed to 0.030-inch over, with a deck plate. It was all oiled and
fresh, sealed in a polybag. I ripped it open and had it on an engine
stand faster than you can say "speed freak." A quick check with my
econo dial bore gauge showed that the holes were indeed straight, round
and 0.030-inch over. Some more rummaging turned up the crank bought at
the same time as the block, an uncut original with no more than light
scuffing, nothing you could even catch your fingernail on. A set of
forged, stock-compression-ratio pistons came out of the depths, as did
a complete set of sleazy-looking, rusty, stock rod forgings, with
pin-bushings intact.

So I set out to assemble the world's fastest short block. Fastest in
assembly time, that is. Within one hour I had the crank polished and
washed, had turned up a new set of Michigan 77 full-groove mains and
had the crank spinning freely-maybe too freely. Yup. Plastigauge
revealed 0.0035 inch on the mains, too much for me. So I did the
unthinkable and decided to part with an NOS, in-the-box-and-cosmolene,
original '68 340 forged crank. Dropping this one in brought the
clearance down to a more realistic 0.0025 inch. Satisfied, I turned my
attention to the rods and pistons.

The rods looked pretty sorry. A fairly heavy layer of rust was
everywhere. A full boogie glass-beading and/or shot-peening was what
they needed, along with, probably, resizing. What they got, though, was
a wire-brushing and a trip through my parts washer. Ditto for the
pistons and pins. I even had to reuse the pin clips, something I
generally don't like to do.

Now I came to the next stumbling block. Rings. All I could find at
midnight was the set of used file-fit Speed-Pros that were on the
pistons. Shoving them into the bores for a try-out revealed a top-ring
clearance of about 0.024 inch. Loose, yes, but not crazy. Remember, we
weren't trying to set any world's records, just slam home a decent
short block.

Next question: What would be the ramifications of using recycled
rings in "new" bores? Would the rings seat? Would there be 50 percent
leak down, or what? We were going to find out!

In what seemed like no more than 15 minutes, I had the short
assembled, using a nice new set of rod bearings previously garnered
from Mopar Performance. (The initial plan had been to replace the rod
bearings in the original mill as preventative maintenance.) Next, I
ripped the cam out of the old motor, along with the timing chain,
sprockets and lifters. This was the best of the old motor, as the
previous owner had recently installed the Mopar Perf. 280-degree cam
and related items. Then I got zapped. When I went to install the crank
key, OH NO! NO KEYWAY! Right. The brand-new crank was defective, having
missed the keyway-cutting operation. At this point I crawled upstairs,
degreased myself and decided to sleep on it.

Next morning, I ripped open another crank box, my last one. This one
had a keyway, thank God. I ripped out the pistons and dumped in the
number two new crank, this time not even bothering to Plastigauge
things. The used rings still bothered me, though. I called Frank at
F&C and he said that he wasn't crazy about the used rings either.
He told me he could have a new set of 0.035-inch Speed-Pros the same
day. I said, "Go for it!"

That night I file-fitted the new rings, going for 0.016 inch on the
tops, 0.010 inch on the seconds. I felt much better about the whole
motor now. Feeling hot, I kept on trucking. I pulled the pan and oil
pump off the old mill and slapped them on. Then I torqued up Frank's
meticulously prepared heads, using a complete set of Mopar Performance
valve train components, including chrome moly retainers, hardened
split-locks, new repro springs, "motor home" Viton valve seals and
hardened rocker arms. I also used MP's "wire-ring" head gaskets to
reduce the compression ratio a bit and head off (pun intended!) any
sealing problems. I then bolted up a new aluminum intake, also from MP,
along with the original ThermoQuad carb. A set of original '68 340
exhaust manifolds would have to suffice on the outlet side, headers
having been deemed undesirable for an event of this type.

While the mill was out I used the opportunity to swap in a new
"police firm-feel" steering chuck from Mother Mopar. This turned out to
be the largest single improvement in the whole car.

By 2:30 a.m. the mill was bolted in, with just "minor" details, like
water pump, A/C compressor and the alternator, standing in the way of

The rest is rather mundane. The motor started on the first try, and
the rings seemingly seated instantly. A few hundred miles of shakedown
revealed no problems and a tight, strong-running motor. Now I figured
that I had about 10 days left to sort things out, mount and balance our
new Toyo tires and attend to various miscellanies. Wrong again.

Bright and early the next morning, March 21, Frank Pogoda hit me
with more "good" news. The trucking company called to say they needed
the car a week earlier than originally planned, meaning the next day! I
said: Forget it! It's just not ready. Franco frantically called every
transportation company in Hemmings and found one that would agree to
pick up the car a bit later and still guarantee its arrival in L.A. on
time. They wanted it on March 25, leaving me just four days to finish
things up. Did I have a choice?

I shifted into high gear, but everything fought me tooth and nail.
Mounting up our Toyos on a freshly painted set of 15x 7- inch HD steel
wheels revealed that one wheel was bent, requiring another trip back to
Mike's County Auto for another wheel to be painted. Our front-end
maven had the flu and couldn't align the beast until the day before it
was due to be shipped. A hastily ordered fuel cell proved to be the
wrong size, and the right one had to be Fed Exed in. It was, in fact,
installed only four hours before the car was loaded on to the trailer.

You get the gist. It was a real true-to-life nightmare.

How'd we do it? Did my potpourri motor hold up? Did we hold up? Did we get arrested?

For more by Rick Ehrenberg, click here!

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