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Author Topic:   Biggest lift for heads
posted September 28, 2003 05:57 PM
.480 would be pushing it, the tops of the guides need to be cut down for retainer clearance.

5500 rpm even with a rv type hydraulic will pull out press in studs.

posted September 30, 2003 09:08 AM
Ya, somewhere right around .500" lift is the most I'd try. And to do that you'll need .100" longer valves so the retainers don't hit the guides. It's not so much the lift as it's the spring pressure. You can get by on a .500" lift flat tappet with 280ish# of spring pressure. Above that, you need more open pressure and that'll pull the studs out.

posted September 30, 2003 08:12 PM
Because someone who obviously knows more than you, clearanced the guides, and or surely installed .100 long valves.. and they also had to elongate the pushrod slot in the heads.

In other words your heads are not stock.

posted September 30, 2003 11:35 PM
I've run .543 lift with standard valves and Z/28 springs but the studs pull up if you don't pin em and you can figure on breaking a rocker stud once in a while. The last set I had pinned cost about $30 extra.

posted October 01, 2003 08:35 PM
stick with it will work

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