342

We have run these rocker arms on our 305, 342 and also run them on our Briggs V-twin. Part # 690972 from Jacks Small Engine $8.50 each
 
we run reinforced stock 342 rockers. Dual springs from Jimbo. SS valves. Dyno cam. My son figured a way to do this with 3/4 in 4130 tubing. Cut and fit. Then TIG weld with SS rod on both sides where they tend to split. Ran last time to 7800 RPMs. No Issues. The Rocker Arm Geometry must B correct! The design ratio is apprx 1.5 to 1.0 We also instd 1/4-20 heli-coils. and used Gr 8 SHCS to hold the Trunions [trunion hole must B opened to 1/4 in Also-use a Carbide drill-MSC] down to the head on I and X. If anything [block-head ] is Milled you will have to use custom length pushrods [We use a Comp Cams make them yourself kit] hope this helps IF you have problems in the future
 
http://www.fastermotors.net/WhatsNew.html

In my opinion 32 pounds of seat pressure is not enough when you have as large of a valve and the acceleration rate you get with the stock 1/3 rocker arms. If you go to a 1.5 ratio you are really asking for trouble.
There are more engines destroyed by not enough valve spring pressure than too much.
 
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