Oldsmobile Diesel Technical Magazine
The choice of many performance engine builders. When it comes to rocker arms, full roller rockers free up the resistance that is present with the stock "metal to metal" rockers and bridges. This not only releases some power through reduced friction, but also reduces heat and stress from the entire valve train. And thats just fine with me! Years have passed by, and new developments have been brought foward into the Oldsmobile Performance World - giving you a choice when it comes to installing them on your Diesel.
The Oldsmobile Diesel engines (4.3 V6, 4.3 V8, and 5.7L V8)are extremely close to the Olds Gas V8's valve train. This means that the use of roller rockers is possible by installing a stock ratio (1.6) set of performance roller rockers listed for use on Oldsmobile V8 Gas engines. There are now a couple of choices in the matter.
Your standard Oldsmobile V8 Stud mounted Roller Rockers: From what I have learned, the only way to properly install the stud mounted rockers is to have the rocker arm bosses on the heads machined down to compensate for the thickness of the pushrod guide plates, which are needed to keep the rocker still as it moves. It will also be necessary to have the rocker arm bolt threads drilled and tapped oversize to 7/16" since there is studs with no guide plates for each rocker. These sets are excellent, and priced reasonable. But they are not a bolt on installation.
Another option, is the new pedistal mount roller rockers for Olds V8s. There is no machine work necessary, and they can be installed with out pulling the heads - just pull the valve covers! They are non-adjustable. However, the pushrods on engines with hydraulic roller lifters (DX) are a little too short for use with these sets. The sets come with 5/16 bolts. The installation of these on the 4.3 V6 Diesel would require the purchase of 10mm x 1.5 bolts to hold them down.
More details on these "bolt on" rocker sets will arrive as the project is completed. Custom pushrods are in progress as of April 5, 2006. This will make it a bolt on installation. So stay tuned....
Any of the above would make a nice combination with ported and polished heads...if you have them off of the engine, of course.