I got a new cam from Butler, their proprietary Comp Cams RAIV "041" grind. The cam card is shown below. The pushrods are the RAIV 11/32 diameter 9.2" units. Before I put everything back into my engine, I need to know why I had multiple pushrod failures and ultimately lifter/cam destruction with what seems to be stock pieces. Too much spring pressure? I'm thinking not, since the heads were assembled many moons ago by very competent Pontiac loving machinists. Somehow my valve train geometry is off.
In H-O Racing's "Heavy Duty Parts and Specs" book I noticed that the 1969-70 RAIV lifters had a ball height of 1.659 and a travel of 0.050 as opposed to 1956-79 all V8 which used lifters with a ball height of 1.759 and a travel of 0.125. First of all, what is "ball height" and can the 0.1" taller standard lifters cause my problems? I have a set of standard lifters ready to go in.
Photo #2 shows the spring paramaters for the springs that Butler recommended.
We should be well under coil bind. Is "seat load" the installed seast pressure?
Valve spring specs for the 1970 RAIV show 39# tension @ height of 1.78 and spring rate 110 (Intake), 76# @ 1.81 with spring rate of 281 (Exhaust).
Will the new springs work? What do the numbers mean in layman's terms?
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