4340 Billet 1.8BP Intake / 1.7BP Exhaust
Billet T6 Aluminum Stands
.250 Wall Hard Chromed Rockerarm Shafts
Intake Info :
We have taken an aggressive approach in the design of our Top Alcohol and ProMod intake rockerarms. It has been designed to be an upgrade replacement for the intake rockerarm being used today in the Top Alcohol, “A” Fuel and Pro Mod categories. Changes have been made in several areas to improve the performance of the valve train. This will help correct some physical geometry issues that have come about through cylinder head changes over many years. Changes in valve lift, increased spring pressure, installed spring height and changes in the location of the intake rockerarm shaft have made it necessary to correct the valve side fulcrum length of the rocker body. This change locates the roller bearing closer to the center of the valve which decreases the possibility of the bearing running off the edge of the contact patch. The fulcrum length, on the pushrod side of the rockerarm, is also increased to correct the rockerarm ratio. These corrections provide additional pushrod clearance and applications where a 7/16” diameter pushrod is being used it becomes possible to increase the pushrod diameter to 1/2”. This improves the stability of the valve train at engine speeds above 8,500 RPM and as high as 11,000 RPM+.
Exhaust info :
The standard features of the Manton “I-Beam Rockerarm” were incorporated into the design with the prime intention of increasing the strength, stiffness, stability and reliability required in the Top Alcohol and Pro Mod categories. The I-Beam rocker design is not a new idea, in fact it is far from it. No one can claim to have the Original I-Beam Rockerarm. If we look back in history we will realize that the original Chrysler early HEMI rockerarm was an I-Beam. Many other rockerarms designed as far back as 1918 were I-Beams. With that said, it is the preferred design theory when it comes to structural strength and stiffness. That is true whether we are designing a building or a rockerarm. Top Fuel engine assemblies produce cylinder pressures approaching 24,000 PSI. A-Fuel engines are in the range of 13,000 PSI. In this case the exhaust rockerarm must be as strong as possible and at the same time stiff enough to maintain valve train control. The Manton Roller Tip, I-Beam Rockerarm provides the highest strength to weight ratio of any design configuration. We use 4340 steel billet to manufacture all of our billet rockerarms and each rocker body is heat treated to 305,000 P.S.I. This is not a forged rockerarm, it is a true billet rockerarm providing perfect grain alignment, which improves reliability and consistency. An oil passage supplies engine oil pressure to the adjusting screw which minimizes the possibility of pushrod galling. This also limits unwanted and unnecessary oil spillage and oil pressure loss. The roller wheel has been increased in size to a very large .5710” diameter and the pin to .2756”. The increased pin diameter is necessary to maximize the strength of the roller which has become increasingly important as cylinder pressures continue to increase.
Intake Rockerarms Are also available in a 1.9 Ratio
if you have any additional questions please feel free to Email or Call us !
Made in America!