It’s a Hemi

My “It’s a Hemi” teeshirt. (Look carefully, and ya see “So-Cal Speed Shop, established 1946;” and “392 cast-iron Hemi.”)

“It’s a Hemi” (“hem-EEE;” not “he-me”),” my mower man said, looking at my teeshirt.
“You’re the second one that noticed,” I commented. “I should wear this teeshirt more often.”
(First was at my bus-union hall earlier that day to elect officials.)
“And it’s the original ‘FirePower’ Hemi,” I added; “1951 through 1958.”

A Hemi head.

Front-elevation line-drawing of a Hemi motor.

Combustion-chambers were hemispherical (“Hemi”) with intake and exhaust valves on each side. Intake-valves therefore aimed at the intake-manifold, and exhaust-valves aimed at the exhaust headers.
A regular V8 had all its valves side-by-side in a row. Intakes aimed slightly at the intake-manifold, but exhausts aimed that way too — not at the exhaust headers.
Chrysler’s Hemi wasn’t overhead-cam; its camshaft still down in the engine block. Different-length valve rockers on two rocker-shafts were used to activate the valves.
The Hemi was what all drag-racers fell to, because it could be so powerful. One was Don “Big-Daddy” Garlits (he preferred “Swamp-Rat”) of Tampa, FL.
In the mid-‘60s I went to Cecil County Drag-o-Way in northeastern MD; Garlits was matched with a fuel-burning Chevy that won because by not being supercharged it was so light.


Garlits’ dragster (a B-block Hemi). (Long-ago photo by BobbaLew.)

Garlits was also burning fuel — model-airplane fuel composed of nitromethane = extremely explosive.
A Hemi was extremely heavy with cast-iron cylinder-heads. But It breathed extremely well, especially at high revs.
Garlits was cranking 1,600 horsepower or more at that time.
I’ll never forget it! That’s goin’ to my grave!
Sheets of white flame perhaps 15-20 feet long emitted from the exhaust headers every time Garlits goosed the motor.
The two dragsters staged at the starting-line: Chevy versus Garlits.
“Blink-blink-blink-blink” from the starting lights, the so-called “Christmas-Tree.” All were yellow except the last, which was green.
The Chevy red-lighted = a jumped start; too early. Garlits started right, but holy mackerel, he blasted right past the Chevy!
He spun his tires the whole length of the quarter-mile, the entire strip!
199.10 mph, 7.70 seconds — the Chevy did 188.03 at 8.03.
Dragsters are much faster now, well over 300 mph - towards 350.
Back then 200 mph was amazing.
The smell of nitromethane filled the air.
“In 1957 and ’58,” I told my mower-man; “people raced their Chrysler 300s the entire length of the Pennsylvania Turnpike, Philadelphia west, to see who got to Ohio first.” (The first 300s were the original Hemi.)
“And that was back when the Turnpike didn’t have a divider barrier.” Closing speed for a head-on was usually over 100 mph, higher if boomin’-and-zoomin’.
Drag racing has moved past Chrysler’s Hemi. Purpose-built motors held to the Hemi format, pushing 11,000 horsepower.

An early Hemi (“FirePower”).

A B-block Hemi (426 cubic-inches).

A current Hemi.

The Hemi has been through three iterations.
First was the original Hemi, 1951 through 1958. It was so costly to manufacture, Chrysler moved to a more normal V8, its “B-block.”
The second Hemi was Hemi heads on the B-block, at the request of NASCAR racers.
Chrysler had to make it street-available, which they did. But NASCAR eventually outlawed the Hemi.
The B-block had to be modified some to make it race-worthy.
Buddy Baker qualified a Hemi Daytona at Talladega Superspeedway at slightly over 200 mph.

Groceries in this thing?

The final Hemi is what’s currently available. I know not if it’s hemispherical combustion-chambers. What I perceive is Chrysler cashing in on the Hemi’s reputation.
It’s pretty strong, and a 392 is available. 392 cubic-inches is final displacement of the original Hemi.
At least it’s aluminum, reversing mind-bending weight.
B-block Hemi’s are available as crate-motors. Swap out your sick Hemi, or lessor, for a brand-new crate-motor.
I don’t get much reaction for my “It’s a Hemi” teeshirt. I don’t expect to; it’s just a teeshirt.
Only car-guys — they know. (“All bow to the mighty Hemi!”)

• The rotating “camshaft” is what actuates the valves. Most engines have a single camshaft down in the block, but it can be atop the cylinder-head, which is more direct and precise. “Double overhead camshaft” is two overhead camshafts, one for intake, and the other for exhaust. Often such arrangements have four valves per cylinder instead of two. Four valves  breathe better.