Mopar 318 'High Performance' vs Chevy 327/250 HP ~ 327/275 HP ~ 350/255 HP
1968 Chevrolet 327/250 HP ~ Code 'L-73'
This combination was available in 1968 {only}.
Available in the > Chevelle and 'larger' Cars.
Compression Ratio ............ 8.75-1
Pistons ............................ Flat Top
Cylinder Heads ................. Casting #3917293
Combustion Chamber ........ Factory {75.34 CC} ~ Minimum {68.8 CC}
Valves ............................. 1.75" Intake ~ 1.50" Exhaust
Camshaft {Hydraulic} ....... #3896929
Lift ................................. .390" / .410"
Duration .......................... 253* / 264*
Duration @ .050" .............. 195* / 202*
Overlap ........................... 34.5*
LSA ................................. 112*
Intake ............................. Cast Iron Dual-Plane
Carburetor ....................... Rochester 4-MV 'Quadrajet' {730 CFM}
The Rochester Quadrajet is rated at 730 CFM, but air-flow is adjusted to
630 CFM on a 'low-performance' Small-Block.
Exhaust System ............... Single
Header Outlet Size ........... 2.0"
Primary Pipe .................... 2.50"
Tail Pipe .......................... 2.0"
The 'optional' {N-10} Dual Exhaust System could be ordered with the L-73
Engine.
Generally speaking, lots of the 1968 Chevelle guys did quite well with the 327/250 HP in Stock Class in the NHRA back-in-the-day.
Difference between '1968' 327/250 HP and the 327/275 HP
The 327/275 HP ~ {Code L-30}
* Compression Ratio ......... 10.0-1
* Cylinder Heads ............. #3917291
* Combustion Chamber .... Factory {63.30 CC} ~ Minimum {57.50 CC}
* Valves ......................... 1.94" Intake ~ 1.50" Exhaust
* Exhaust System ............ Single
* Header Outlet ............... 2.0"
* Primary Pipe ................. 2.50"
* Tail Pipe ....................... 2.0"
The 'optional' RPO N10 'Dual-Exhaust' System was offered at a minimal price.
* Same pipe size, just with 'dual piping'.
The Camshaft {Valve Train}, Intake Manifold and Rochester 4-MV Quadrajet Carburetor
were the same components.
