'383' ~ 1967 325 HP vs. 1968 330 HP vs. 1968 335 HP
The Heads
1967 Casting #2406516
* Closed Chamber ...... 73.5 CC's {Minimum} ~ 79.0 CC's {Factory}
* Intake Valve ........... 2.08"
* Exhaust Valve ......... 1.60"
* Intake Flow ............. 192 CFM @ .440" Lift
* Exhaust Flow ........... 124 CFM @ .440" Lift
Note;
The #516 Castings were noted for having a smaller-volume Intake Port with a
'flat-floor' design.
Note;
But, the 'Closed-Chamber' design of the #516 Casting, provided for 'a tight quench', which helped develop better compression and power.
Note;
The #516 Castings were noted for having restrictive-curves within the Exhaust Port.
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1968 Casting #2843906
* Open Chamber ....... 79.5 CC's {Minimum} ~ 88.0 CC's {Factory}
* Intake Valve .......... 2.08"
* Exhaust Valve ........ 1.74"
* Intake Flow ............ 203 CFM @ .440"
* Exhaust Flow .......... 145 CFM @ .440"
Note;
The 'Open-Chamber' design provided improved flow, and offered lower emission's at low RPM levels.
Note;
With the 'Open-Chamber' design, there would be less shrouding of the
Valves, which lowered the turbulence within the Combustion Chamber.
Note:
The #906 Castings were listed with having 10% larger volume Intake Ports, which
included an improved flow-design with a radius-type design, as opposed to the
earlier flat-floor design. The #906 Casting Intake-Port provided for increased
performance at higher RPMs.
Note;
The #906 Castings were equipped with larger Exhaust Valves {1.74" to 1.60"},
which was an increase of {+8%} in size. The Valve-Bowl area was also increased to accommodate the larger valve.
Note;
The #906 Casting also had an improved design within the port, as there were less
restrictive bends, which improved flow {+18%}.
