91 L98 Roller Rocker info
Thread Starter
Intermediate
Joined: Sep 2009
Posts: 43
Likes: 0
From: KY
91 L98 Roller Rocker info
Can somebody educate me on these.What works best for my car
1.5 or 1.6 with factory valve covers
Stamped or aluminum/with roller bearings around adjustment nut
Which size stud does my car have 3/8 or 7/16
will i gain 10 HP ?
1.5 or 1.6 with factory valve covers
Stamped or aluminum/with roller bearings around adjustment nut
Which size stud does my car have 3/8 or 7/16
will i gain 10 HP ?
Melting Slicks
Joined: Nov 2005
Posts: 2,736
Likes: 0
From: WAY UPSTATE NY
Both ratios will work but it is advisable to change the valve springs when using 1.6. You have 3/8 studs and will require Self Aligning rockers. 10 HP is debateable.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
It should get you ~10hp at the crank with a full roller setup.The car should have come from the factory with 1.5 stamped rockers on 3/8" studs.
Narrow bodied (for center bolt valve covers) full roller 1.5 rockers should bolt right up. Stamped 1.5 roller rockers with just roller tips are another option and should (check with the rocker manufacturer first) bolt right up. You won't free up as much HP with the just the roller tipped ones.
Narrow bodied (for center bolt valve covers) full roller 1.6 rockers will work but the stock valve covers must be modified to clear. Stamped 1.6 roller rockers with roller tips are also an option and might not (check with the rocker manufacturer frst) hit the stock valve covers. New valve springs are a good idea when going with a longer rocker arm on a high mileage setup. Pushrod geometry should also be checked and adjusted if need be. Check to ensure the rockers will clear the valve springs and that they do no not bind or bottom out on the valve guide....ect
