Factory Buick 4 Bolt 455 Block
by John Fritz
Here is one of two Buick 455 blocks w/4 bolt main caps. There
were two blocks cast as experimental designs for R&D.
Here is a picture of the factory "X" welded on
to the block designating it as an experimental design item.
Here is a closeup of "4" indicating 4 bolt main
The picture said "Pro-stock block" which some of
the folks at Kenne-Bell referred to it as (when I was trying to figure out
"what in the world" this thing was), but it was officially called
the "Stage III" by the Buick Engineers who built it!
This was at one time a complete and running motor! It was
a zenith for the 1970 Buick 455 motor. When delivered to the only other
person than myself, and Buick to own it, it was "Loaded for bear".
Two four sheet metal high rise intake, Stage III Tunnel port
design heads, Stage III cam, 13 to 1 Compression, Gilmore oiling system,
and of course the foundation to it all, the Stage III four bolt main block.
This block is one of only two known to exist. Engineers at Buick went to
great lengths to strengthen any weak points in an already capable block.
Obviously the four bolt mains are of great benefit but the webbing for the
mains is also much thicker and has no "scalloping out" as seen
in standard production blocks. The webbing in the lifter area has also been
fortified to endure flex, in serious applications.
Not personally being an engineer, or having a block currently to visually
compare this one to, I cannot determine other enhancements made to the Stage
History? I discovered this block by total luck back in the late 80's. I
had advertised a fiberglass Skylark hood for $125 in a local paper, when
the ad came out it said $25. Needless to say I had a flurry of calls.I had
always grown up around GS's, and spoke with Richard Lassiter at the very
beginning of his starting the GS Club in the early 80's, so I was more than
happy to talk to any, and all, the Buick guys who called about the mispriced
One of the callers, after a long talk of sharing GS information, gave me
a phone number to call. He said the "Old Man" had Stage 1, Stage2,
Stage 3 parts.
I probably paused too long after he said that, but I was
thinking "OH NO, not another one!" Another person you think knows
Buicks until they say something like "Yea my "Grand" Sport
had a 454 with four bolt mains, vinyl top and was actually a real GSX".
Not to be rude and say "There is no Stage III" I took down the
number. I almost didn't call then I just decided to go for it, maybe he
had something I needed.
This guy KNEW his stuff. When I sheepishly said I'd never heard of a Stage
III, he about hung up on me for second guessing him. He blasted out every
part that was on it, the Buick engineers who delivered and identified it,
and topped it all off by telling me "it even had oil in it, and was
ready to run".
I was standing in his shop the next morning! Getting into "The inner
tomb" of his shop reminded me of the people who explored the pyramids,
on a car level. I lost count of the gates, doors, twists and turns, and
attention grabbing carnage of Buick parts that were scattered everywhere,
leading to the Experimental Block.
Finally under the buzz of a single flickering fluorescent bulb, I stood
over the block, which was on its end, tranny side up, mains toward the wall.
With a flashlight I focused on the puddle of water, from the leaking roof,
that had been there for a good while. I made some small talk about the roof
leak before he finally told me to "spin it around".
There they were. Factory four bolt main caps. I stirred up
the water when I moved the block, as I reached down to scoop the water out,
I saw a large "X" cast into the area, Buicks sign for Experimental
(believe these were on the Proto-type Detroit Auto show 1970 GSX ,which
gave away it's history) products. I was literally shaking, I was so excited
about finding this incredibly rare, and forgotten part of Buicks "Stage
Through one particular sequence of numbers on the block,
it was finally identified by the Head of the Stage program as one of there
original R&D pieces. He said " That is our Experimental Work Order
number, You've got a very rare piece there, we only made a handful of those,
take care of it." He asked me if there was anything else he could answer
but since he called me, caught me off guard, and floored me with the confirmation,
all I could do was say "No Sir, and Thank You!"
Today it sits safely in a special display case ,being treated with the respect
it deserves. I hope one day to be able to show it at the GS Nationals. It
would definitely give us something new and different to look at and think
about, "What if this whole package had made it to production before
the 70's gas crunch?" That's one GS I'd love to drive!
Hope everyone enjoys the info. Before anyone asks, all the
scattered parts the original owner had are gone. Someone went in and cleared
him out shortly after I plucked the Experimental block out. Additionally
all the other parts to the block, were stolen back in the 70's, by a dishonest
nephew the owner employed. Why did he miss the block? Probably the same
reason I would have back then."Just another ole heavy block, nothing
How wrong they were!