1964 Plymouth Belvedere 'Sedan' ........................ 1968 Plymouth Road Runner 'Coupe'
426-S 'Street Wedge' ................................................... 383 Road Runner
Bore............................ 4.25" ............................................ 4.25"
Stroke......................... 3.75" ............................................ 3.375"
Compression ............... 10.3 - 1 ......................................... 10.0 - 1
Piston Type.................. Flat Top ......................................... Flat Top
Piston Height................ {-.051"} Below Deck ...................... {+.21"} Above Deck
Camshaft..................... Hydraulic ........................................ Hydraulic
Lift............................. .431"/.431" ..................................... .450"/.458"
Duration...................... 268*/268* ....................................... 268*/284*
Overlap....................... 48* ................................................... 46*
Cylinder Head.............. #2406516 ......................................... #2843906
Combustion Chamber.... Closed ................................................ Open
CC Level {Factory}....... 79.5 .................................................... 88.0
CC Level {Minimum}..... 74.5 .................................................... 79.5
Intake Valve................. 2.08" ................................................... 2.08"
Exhaust Valve............... 1.60" ................................................... 1.74"
Valve Spring {Closed}... 134 lbs. ............................................... 134 lbs.
Valve Spring {Open}..... 208 lbs. ............................................... 258 lbs.
Intake Manifold............ Cast Iron .............................................. Cast Iron
Style.......................... Dual Plane ............................................. Dual Plane
Type.......................... Low Profile ............................................ Low-to-Medium Profile
Carb Pad Height.......... 3.30" .................................................... 3.44"
Carburetor................... Carter AFB {#3611} .............................. Carter AVS {#4426}
CFM............................ 575 ...................................................... 625
Throttle Bore................ 1.437" x 1.563" ..................................... 1.437" x 1.686"
Venturi Size.................. 1.186" x 1.313" ..................................... 1.186" x AV
Exhaust Manifolds
Style........................... Log Type ................................................ Swept Design
Outlet.......................... Rear Exit ................................................ Rear Exit
Outlet Size................... 2.25" ...................................................... 2.50"
Primary Exhaust Pipe.... 2.25" ....................................................... 2.50"
Tail Pipe...................... 2.25" ....................................................... 2.25"
Horsepower................ 365 @ 4800 RPM's ...................................... 335 @ 5000 RPM's
Torque....................... 470 Ft/Lbs. @ 3200 RPM's............................ 425 Ft/Lbs @ 3400 RPM's
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Shipping Weight............ #3465 lbs. ............................................... 3422 Lbs.
Weight-to-Horsepower... 9.52 ........................................................ 10.21
1964 NHRA Class.......... A/Stock {9.50 - 10.59 Wt/Hp} ................... 1968 NHRA Class .... E/Stock {10.00 to 10.49 Wt/Hp}
NHRA 'Stock' Horsepower Ratings
* {1964}... 365 HP ........ 9.52 Wt/Hp = {A/S}
* {1968}... 365 HP......... 9.52 Wt/Hp = {D/S} ----------------------- {1968} ... 335 HP.... 10.21 Wt/Hp = {E/S}
* {1969}... 365 HP......... 9.52 Wt/Hp = {E/S} ----------------------- {1969} ... 335 HP ... 10.21 Wt/Hp = {F/S}
* {1970}... 365 HP......... 9.52 Wt/Hp = {F/S} ----------------------- {1970} ... 335 HP ... 10.21 Wt/Hp = {G/S}
* {1973}... 365 HP......... 9.52 Wt/Hp = {D/S} ----------------------- {1973} ... 335 HP ... 10.21 Wt/Hp = {E/S}
* {1976}... 340 HP........ 10.19 Wt/Hp = {E/S}----------------------- {1976} ... 320 HP ... 10.72 Wt/Hp = {F/S}
* {1979}... 325 HP........ 10.66 Wt/Hp = {F/S}----------------------- {1979} .... 315 HP .. 10.86 Wt/Hp = {F/S}
* {1991}... 320 HP........ 10.83 Wt/Hp = {F/S} ---------------------- {1991} .... 310 HP ... 11.04 Wt/Hp = {G/S}
* {1995}... 315 HP........ 11.00 Wt/Hp = {G/S} ---------------------- {1995} ... 300 HP ... 11.40 Wt/Hp = {G/S}
* {2002}... 300 HP........ 11.55 Wt/Hp = {H/S} ---------------------- {2002} ... 300 HP ... 11.40 Wt/Hp = {G/S}
* {2012}... 296 HP........ 11.70 Wt/Hp = {H/S} ---------------------- {2012} ... 300 HP ... 11.40 Wt/Hp = {G/S}
* {2013}... 291 HP........ 11.90 Wt/Hp = {H/S} ---------------------- {2013} -- 300 HP ... 11.40 Wt/Hp = {G/S}
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* Tested Cars {Stock Components} 4-Speed, w/3.91 Gears and 7" Cheater Slicks
* Performance.......... 14.26 @ 97.50 MPH .................................. 14.28 @ 99.77 MPH