Old School 'C/FX' 273

[69 Cuda 440]

C/FX Class

Small Block Engine in a mid-size Car.

C/FX = 13.00 Weight-to-Cubic Inches

In June 1965, right after the NHRA Springnationals.

Dave Koffel converted his 1965 Plymouth A-990 {SS/A} 426 Race Hemi into
a C/FX terror by swapping in a highly modified 273 Small Block.

[URL="http://www.thevintageracer.com/65ssntl/1965-005.jpg"][URL="http://www.thevintageracer.com/65ssntl/1965-005.jpg"][/URL][/URL]

 

[moper]

I'd love to see/hear more about that one... Wicked cool...

 

[69 Cuda 440]

June 1965

Dick Maxwell {Head of Chrysler Performance} talked Dave Koffel into campaigning
in the 'C/FX' Class for the second-half of 1965.

The 1965 Plymouth A-990 ~ 4-Speed ~ 426 Race Hemi {SS/A} was replaced with a
273 Engine.

The 1965 A-990 with the 273 4-Speed would weigh in at 3570 lbs.

3570 lbs. ~ 273 = 13.07 Weight/Cubic Inches
* C/FX Class = 13.00 and up

In early 1965, the C/FX National Record was a 'soft' 13.92 @ 101.46 MPH.

In NHRA Racing, a C/FX Class Winner would compete in Stock Eliminator
against Stock Class winners.

At the time in 1965, the hottest car in C/FX was a 1965 Ford Galaxie 500 '289'
driven by Bill Hoefer {California}, who was backed by the Ford Racing Division
on the West Coast.

 

[69 Cuda 440]

1st Time Out .........

July 16, 1965 @ Muncie Dragstrip, Indiana

NHRA Division 3 Gold Cup Meet

Dave Koffel crushes the C/FX National Record {13.92 @ 101.46 MPH}
with a 13.45 @ 103.21 MPH.

[URL="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTZErduCTGx9uNQkunbQti7JGgXPt9lahelznMpl_uKY5rlsoSb"][URL="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTZErduCTGx9uNQkunbQti7JGgXPt9lahelznMpl_uKY5rlsoSb"][URL="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTZErduCTGx9uNQkunbQti7JGgXPt9lahelznMpl_uKY5rlsoSb"]
[/URL][/URL][/URL]

 

[toolmanmike]

I see a flaw in your math. Is it weight to cubic inch or weight to horsepower? Weight to cube is: 3570 lbs. ~ 273 = 13.07 Wt/Hp

 

[69 Cuda 440]

I see a flaw in your math. Is it weight to cubic inch or weight to horsepower? Weight to cube is: 3570 lbs. ~ 273 = 13.07 Wt/Hp

T-M-M,

C/FX was ........... Weight-to-Cubic Inches

My error on 13.07 Wt/Hp ......... :violent1:

It should be '13.07' Weight-to-Cubic Inches

 

[toolmanmike]

T-M-M,

C/FX was ........... Weight-to-Cubic Inches

My error on 13.07 Wt/Hp ......... :violent1:

It should be '13.07' Weight-to-Cubic Inches

No harm/ no foul. I was thinking they might have used the 275 horse D Dart engine. LOL

TMM

 

[69 Cuda 440]

Original Engine Specs

Engine............................ 273
Crankshaft...................... Standard 273 Forged Unit {Casting #2128869}
Main Bearings................. 'Federal-Mogul' Fully-Grooved {Upper} and Standard {Lower}
Connecting Rods............. Standard 273 'Shot-Peened'
Connecting Rod Bearings.. 'Federal-Mogul'
Pistons........................... JE Lightweight ~ 10.5 - 1 {+.140" Dome}
Rings............................. Dykes {Top Compression} ~ Low-Tension Oil Ring
Oil Pan .......................... 9 3/4" Depth w/Baffle {8 Quart}
Oil Pump........................ Mopar High-Volume
Oil Pump Pick-Up............ 426 Max-Wedge 180* Swivel

Deck Block .................... {- 011"}
Piston Dome Height........ {+.129" above block}

Cylinder Heads............... Standard 273
Intake Valve.................. 1.94" {354 Hemi}
Exhaust Valve................ 1.56" {354 Hemi, cut down}
Valve Seats................... 5-Angle {70*, 60*, 50*, 45*, 40*}
Valve Seat Top-Dress...... 0*
Seat Angle Depth........... 1"
Combustion Chamber..... 51.3 CC
Net Compression........... 12.5 - 1

* Note: Porting is not allowed in C/FX Class. Only 'approach angle' valve-seat/bowl-blending at 1" depth maximum.
* Note; Cylinder Block notched {eye-browed} to allow for Valve clearance.
* Note; Valve-to-Piston clearance set at .060".
* Note; Internal components balanced.

Camshaft.................... Racer Brown #ST-12 'Mechanical'
Lift............................ .480"
Duration..................... 284*
Overlap...................... 60*
Centerline................... 108*

Valve Springs.............. Racer Brown
Outer......................... #VR-18x
Inner......................... #VR-56
Installed Spring Height. 1.68" to 1.70"
Load Rate................. #130 lbs. Valve-Closed ~ #313 lbs. Valve-Open

Lifters........................ Chrysler Hemi Tappets {-.0005" Undersize}

Intake Manifold............ Edelbrock #D-66 {In-Line Dual-Plane Dual Quad}
Modifications............... Port Runner/Gasket Matched ~ Throttle Bore Openings Chamfered 1/4" Depth, Smoothed and Polished

Carburetors................ {2} Carter #3853S ~ 1965 273 Manual ~ {460 CFM} ~ 1 7/16" Primary and 1 9/16" Secondary
Mopar Tech Adjusted...
Front Carburetor......... Remove 'Step-up Springs' from Primary Metering Rod ~ Install {Primary} #16-216 Metering Rods
Rear Carbretor............ Install {Secondary} #120-176 {.0635" Jets} ~ Install lighter 'Velocity Valve Springs'

 

[toolmanmike]

Pretty impressive specs. Too bad hey couldn't port the heads but the 5 angle valve seats with larger valves had to help. 12.5/1 doesn't hurt either. Fun! tmm

 

[69 Cuda 440]

T-M-M,

The '1st' 273 'C/FX' Engine was putting out between 315 and 320 Horsepower.

Included were;
* Stahl Custom Designed Headers
* Primary Tubes .......... 1 3/4" Diameter
* Tube Length ............. 30"
* Extension ................. 3 1/2" Diameter x 8" Length
* Collector .................. 12" Length {O.D. Tapered down from 3 1/2" to 3"}
* Outlet Opening ......... 2 7/8" Diameter O.D.

* Header Flange Thickness = 1/4" {to prevent scavenging}

Note: The primary tubes 4-Pipe 'clover-leaf' connection in the 'extension' had the center section
closed off and brazed with sheet-metal. This was to prevent back-flow pressure from effecting
the exhaust flow between the tubes.

 

[toolmanmike]

I wouldn't mind finding a 64 or 65 B Body with a 273 myself. I am a big fan of the early 60's B's.

 

[69 Cuda 440]

July 23, 1965

York US 30 Dragstrip ~ York, Pennsylvania

NED 1 Points Meet

Just 1-Week after setting the C/FX National Record at Muncie Dragstrip, Dave Koffel
was back at it again.

New Record ........ 13.36 @ 104.45 MPH

 

[69 Cuda 440]

Hot Rod Magazine {February 1966}

Photographs and Interview from November 1965 at Detroit Dragway

 

[moper]

Wicked cool. I wonder what he shifted at? Thanks 69

 

[69 Cuda 440]

Wicked cool. I wonder what he shifted at? Thanks 69

7000 RPM's

Dave Koffel was running 4.56 Gears in the #3570 lb. 1965 Plymouth Belvedere A-990.

The 4-Speed was a 'Slick-Shift' A-833 Transmission.

According to Dave, they scorched the Rod-Journals of the 'stock' Forged Crankshaft 'black'
a few times with several 7000+ RPM shifts.

Then they went to a 'special' Tuftrided 318-3 Crankshaft and 'custom' Howard's Aluminum Rods
and were soon pulling 7500 RPM shifts.

 

[Abodybomber]

Cool thread,something a little different.

 

[toolmanmike]

Cool thread,something a little different.

X2 Where's the "Like" button! lol tmm

 

[70aarcuda]

Paul Wong

65 273 4 speed.

 

[hemidart1]

that car was the inspiration for my '65 Belvedere build!

Video of the car!

[ame="https://www.youtube.com/watch?v=2HxX07hJfEA"]https://www.youtube.com/watch?v=2HxX07hJfEA[/ame]

 

[Abodybomber]

that car was the inspiration for my '65 Belvedere build!

Video of the car!

[ame="https://www.youtube.com/watch?v=2HxX07hJfEA"]https://www.youtube.com/watch?v=2HxX07hJfEA[/ame][/QUOTE


That, rocks....

 

[toolmanmike]

Sounds great! We need information on the build.....inquiring minds want to know! lol

 

[69 Cuda 440]

Dave Koffel 'C/FX'

According to Dave Koffel, on paper the modified 273 in the 1965 Belvedere was going to run
under the 13.92 @ 101.46 MPH National Record.

After 2-Weeks of testing at Dragway 42 in West Salem, Ohio in early July 1965, the 'C/FX' car
was running in the 13.50's @ 103 MPH.

But, they were cooking the Crankshaft {black rod journals}.

They switched the 'stock' Forged 273 Crankshaft with a 318-3 'Tuftrided' Crankshaft from a 318 Truck.

On July 16th, at Muncie Dragstrip in Indiana at the Division 3 Gold Cup Meet, they smoked the record
with a 13.45 @ 103.21 MPH {Below}

[URL="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTZErduCTGx9uNQkunbQti7JGgXPt9lahelznMpl_uKY5rlsoSb"][URL="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTZErduCTGx9uNQkunbQti7JGgXPt9lahelznMpl_uKY5rlsoSb"][URL="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTZErduCTGx9uNQkunbQti7JGgXPt9lahelznMpl_uKY5rlsoSb"][URL="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTZErduCTGx9uNQkunbQti7JGgXPt9lahelznMpl_uKY5rlsoSb"][URL="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTZErduCTGx9uNQkunbQti7JGgXPt9lahelznMpl_uKY5rlsoSb"][/URL][/URL][/URL][/URL][/URL]


After that July 16th meet, they pulled the 273 Engine and brought it to 'D & D Engine Rebuilders' in
New Brighton, Pennsylvania for a quick refreshing.

They swapped out the 'stock' Forged Connecting Rods for a set of 'custom' Howard's Aluminum Rods.

1-Week later

On July 23rd at York US 30 Dragstrip in York, Pennsylvania at the NED 1 Points Meet, Dave lowered
the C/FX National Record to 13.36 @ 104.45 MPH.

 

[hemidart1]

sorry to say that the original 273 from my car was beat too hard to bring back. So in it's place is a thinly disguised 360- original replacement motor from '74 (just put together now), 1968 340 intake, Edelbrock 650 thunder series, Hughes Whiplash 340/360 cam, billet valve train, TTi headers, Mopar ignition
..and of course 273 valve covers and breather.

 

[toolmanmike]

sorry to say that the original 273 from my car was beat too hard to bring back. So in it's place is a thinly disguised 360- original replacement motor from '74 (just put together now), 1968 340 intake, Edelbrock 650 thunder series, Hughes Whiplash 340/360 cam, billet valve train, TTi headers, Mopar ignition
..and of course 273 valve covers and breather.

That sounds like lots of fun! I thought it had a deeper growl than a 273 has. lol tmm

 

[69 Cuda 440]

More on Dave Koffel

Following lowering his own C/FX National Record on July 23, 1965 at York US 30 Dragstrip.

Dave was back home in Massilon, Ohio.

He pulled out the 273 Small Block. He then re-installed his 426 Race Hemi Engine, to get
prepared for the Big Event on August 7, 1965 ~ the Super Stock Magazine Nationals at
York US 30 Dragstrip

Dave was classed in SS/A {3400 lbs. Weight Class}.

Dave set the 'Low' Elapsed Time at 11.09, and won Class.

But Dave was knocked off by Tom 'Smoker' Smith in Top Stock Eliminator.
-----------------------------------------------------------------------------------------------

Photo Below; At the Super Stock Magazine Nationals

[URL="http://www.thevintageracer.com/65ssntl/1965-005.jpg"][URL="http://www.thevintageracer.com/65ssntl/1965-005.jpg"][URL="http://www.thevintageracer.com/65ssntl/1965-005.jpg"][/URL][/URL]
[/URL]