Roller Tip Rocker Arms???

[383stroker_1]

Hey Guys, I am planning on getting me a set of roller tip rockers for my sbc 383 project motor. Is there anything special I should be aware of when using rollers enstead of the standard rocker arms? I am also thinking of getting the 1.6 ratio rather then the standard 1.5s for alittle bit higher lift. Would there be anything I would need to run with these? Push Rods? I have seen some cases where people use, (I think they are called) girdles or a shaft that hold the rocker arms. Is that recommended or what? Like I have said in previous posts, I am an amateur. I need all the help I can get. LOL Thanks.

[MrPbody]

First, if usiung roller-tipped, buy them based on performance, not price. Comp Magnums are far superior to any other roller-tipped rocker we've used. The Crane units are basically stock rockers with a roller wheel in them (not exactly, but effectively).

No need for stud girdles until lift goes over .600" and spring pressure exceeds 500 lbs. (nose). Roller-tipped rockers are not suited to such cam action.

When changing ratios, you must do a little math, to see what net lift is, after the ratio change. You MAY need to "clay check" to see if there are valve-to-piston clearance issues. If you're now using 1/5:1 rockers, and go to 1.6s, divide the theoretical lift (if hydraulic) by 1.5, and multiply the result by 1.6. That will tell you the "new" lift number.

Whether or not internal changes are necessary depends on what cam is in there now, and what valve springs you're using.

Pushrods, if the correct length, should not be affected by a ratio change.

Jim

[SpinnerCee]

MrPbody is on the money

We've seen cases where just switching rocker arm ratio has created pushrod clearance problems with the head, so you should check.

Ratio changes are usually applied to either the exhaust and/or intake side to compensate or test for inefficiencies in head port or manifold flow -- that said, it may be a better idea to just get a cam with more lift and/or different intake/exhaust numbers (lift, duration).

The roller, on the tip and/or the fulcrum reduces friction in the valvetrain primarily, and secondarily, "good" aftermarket rockers in general are more accurately machined than the stock stamped factory rockers.

Aluminum vs steel is another choice -- aluminum is lighter, but more expensive and less durable than steel (I've seen both broken though).