Originally posted by Razor
So the heads with roller fulcrums started in mid 97..nothing earlier had roller fulcrums?
What is the rocker physical difference between the two ?
The series II 3800 Supercharged L67 engine was first produced in 1996. The series II 3800 was first produced in 1995 but did not replace all 3800 series I engines until 1996.
Pertaining to series II 3800 engines only:
The L36 and L67 all have the same heads. The exception is the L67 heads had bosses machined for injectors. The L36 had these bosses but they were not machined.
ALL L36 and L67 engines 95-present had roller fulcrum 1.6 ratio rocker arms.
Supposidly the head castings changed starting in the 98 model year became "beefier" in order to fix a problem in where cracks could develop around some of the exhaust valve spring seat areas. I have yet to see this happen myself but I have heard stories from people who have done some significant head porting.
There are more differences between the L36 and L67 than someone previously stated. Here is what is different:
-Pistons
-Connecting Rods
-Crankshafts (same part number between L36 and L67 but balanced different to compensate for rods and pistons)
-Intake, Supercharger
-Heads are same casting but machined different
-Valve covers
-Camshaft? some say different, ALLDATA shows same P/N
-Crank balancer (L67 has grooves for 2 belts)
Other than that, block, exhaust manifolds, timing cover, etc are all the same between the two engines.