Stock J Heads - Max Lift?

[Barracootie]

Gang,

Looking over a mild Thumper or Comp Dual Energy 275 cam for my 340 street engine...10:1, 600 cfm, 1 5/8 headers, etc. Max lkift on both of these cams is in the .480s range. Question is, will the stock 340 J head springs support that lift?

Thanks!

 

[moper]

No, stock springs will not function with that cam, or any other that has lift over about .440. Replace them with the recommended springs. My guess is those are 901s, and they drop in place.