Editing Chevrolet big-block engine (section)

==== Mark IV 427 performance specifications ====
{| class="wikitable"
|-
!First<br />Year
!Last<br />Year
!Engine<br />Code
!Features
!Compression<br />ratio
!Factory<br />Gross Power<br />Rating
|-
|1966||1969|| L36 || 4-barrel || 10.25:1 || {{cvt|390|hp|kW|0}}
|-
|1966||1969|| L72 || 4-barrel + solid-lifters, more aggressive cam and high flow cylinder heads||  |11.00:1 || {{cvt|425|hp|kW|0}}{{efn|Chevrolet actually advertised this engine as {{cvt|450|hp|kW|0}} for a short period of time. There is speculation over whether this engine actually put out {{cvt|450|hp|kW|0}} gross, or if this was a marketing oversight that was later corrected.{{cn|date=May 2024}}}}
|-
|1967||1969|| L68 || L36 with 3×2-barrel carbs. ||  10.25:1 || {{cvt|400|hp|kW|0}}
|-
|1967||1969|| L71 || L72 with 3×2 barrel carbs.||  11.00:1 || {{cvt|435|hp|kW|0}}
|-
|1967||1969|| L89 || L71 + aluminum  heads; RPO L89 also applied to L78 "375 HP" 396 engine with aluminum head option. || 11.00:1 || {{cvt|435|hp|kW|0}}
|-
|1967||1969|| L88 || Racing-spec cam, high-flow aluminum heads (casting #s varied by model year) and some upgraded, competition-grade parts || 12.50:1{{efn|L88 had a 12.5:1 compression ratio with closed chamber heads except during the last half of 1969, when it had open chambered heads that yielded 12.0:1{{cn|date=May 2024}}}} || {{cvt|430|hp|kW|0}}{{efn|L88 was rated for {{cvt|430|hp|0}} at 5200&nbsp;rpm.}}
|-
|1969||1969|| ZL1 || Aluminum block with open chamber "3946074" aluminum heads (the early Corvette RPO engine featured a closed chamber head); cam even "hotter" than L88's; upgraded parts similar to L88's || 12.00:1 || {{cvt|430|hp|kW|0}}
|}
'''Applications:'''
* 1966–1969 [[Chevrolet Biscayne]]
* 1966–1969 [[Chevrolet Caprice]]
* 1966–1969 [[Chevrolet Impala]]
* 1966–1969 [[Chevrolet Corvette]]
* 1968–1969 [[Chevrolet Camaro]] (most were dealer installed, but in 1969 both the L-72 and the ZL-1 were factory options)

'''427 production codes:'''
* LS-1: produced 1969, 10.25:1 compression, Q-jet carburetor, oval port closed chamber heads, hydraulic lifters, nodular iron crankshaft, and two-bolt main caps. It produced {{cvt|335|hp|kW|0}}.<ref name="Muscle Cars Magazine p.63">{{cite journal |journal=Guide to Muscle Cars |date=February 1987 |page=63}}</ref>
* L-36: produced 1966–69, 10.25:1 compression, Holley or Q-jet carburetor, nodular iron crankshaft, hydraulic lifters, oval port closed chamber heads, and two-bolt main caps. It produced {{cvt|385|hp|kW|0}} in 1967–68 full-size cars, {{cvt|390|hp|kW|0}} in 1969 full-size cars and Corvettes (by exhaust system).<ref name="Muscle Cars Magazine p.63"/>
* L-68: produced 1967–69, 10.25:1 compression, [[Pontiac V8 engine#347|Tri-Power]], nodular iron crankshaft, hydraulic lifters, aluminum oval port closed chamber heads, and two-bolt main caps. It produced {{cvt|400|hp|kW|0}}, and was used in Corvettes.<ref name="Muscle Cars Magazine p.63"/>