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Author Topic:   cam
Dirt Full Roller

Total posts: 71
posted December 19, 2003 09:36 PM  
Our rules limit us to a 350 lift cam. All of the catalogs list gross lift and even the economy cams are over 350 lift, a stock 305 cam is 357 gross lift. I've seen reference to gross lift, valve lift and cam lift, what is the difference in the three.

Dirt Maniac

Total posts: 168
posted December 20, 2003 06:18 AM  
Wow .350" lift? That is a awful little. Hopefully it is supposed to be .450" But to answer your question, gross lift is cam lift times the rocker arm ratio which is your valve lift also. This is the amount that you valve will lift off its seat at wide open postion, cam lift is only the amount built into your cam. You can't change that but you can change the gross lift by changing rocker arm ratios.

Dirt Freak

Total posts: 257
posted December 20, 2003 03:00 PM  
350 is TINY for sure..... I was undestood that a 305 has a stock lift of .390-.410

Our rules state we "max lift of .420", no duration limits. But .350????? Thats weird....very small lift number. More like briggs and stratton size.

Dirt Forum Champ
Total posts: 5390
posted December 20, 2003 08:40 PM  
are you sure they want gross lift and not cam lift with a 350 cam and 1.5 rockers thats a 525. like m1 said most bone stock 350's came with at least a 390

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