High rpm miss

aaronk785 said

B3RE. Thank you so much for explaining this to me. I must be reading the wrong material. This was tech from a reputable cam maker. Said to change push rod length to get sweep centered. That's the difference between me a garage builder and a pro like yourself. OK. Went out and put in a .150 longer push rod. Sweep is down to just under .040.and right at about .100 from the edge. This is the original set I ordered but they didn't center the sweep. So I went shorter. 7.1 to 6.950. Am I close enough or not? OH! and I think their small block chevy valves. Thanks again for sharing your knowledge. I'll try the sbc rocker to see if that helps if what I have wont work.

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I know, Comp has had this info wrong for a very long time, and doesn't seem to want to correct it. Don't beat yourself up, there are a lot of "pro's" who don't do it right, and bad info in print doesn't help anyone, except maybe the one selling the rockers.

That's still off a fair amount, all things considered. I'd see if you can get it down to .030" or less, and use a SBC rocker if necessary. If you keep lengthening the pushrod, it will get to a breakover point where the sweep will start getting wider again. Making the sweep as narrow as possible, will make the valvetrain a whole lot more stable.

Edit: I misread your post. I thought you went from a +.125" to a +.150" pushrod, and it dropped to .040" sweep. I see now that you went an additional +.150" over the +.125", so effectively +.275". You will have to fine tune with an adjustable pushrod for the narrowest sweep, which may be longer or possibly SHORTER than where you are now. If it needs to be a little shorter, the the existing rockers will work, although it might be a bit nicer with the SBC rockers.