How much lift?

[84cutspreme]

Okay I am not sure if this is in the right forum, but the question is:

With a max lift of .575 on a set of dual valve springs how much lift in a camshaft is a good amount? I am led to believe I need about .050 of clearance to be on the safe side.

 

[LS1GN]

not sure of your question/we'll need more info

PVC? (piston-to-valve) clearance?
rocker ratio?

 

[mebe007]

imo i would have the heads set up specifically to any cam i have or planned on running. thats why i usually buy heads bare or buy them from someone who can set them up specifically for my application. Its not just about the lift its also about the spring pressures needed. Too much and too little are both equally as bead/ destructive. the cam you are currently running should in theory be fine with those springs. im sure you would be fine with a .540 lift cam as well.

 

[Kwik_Cutty88]

.575 is a super agressive cam, but it also wil make a nasty sound. My Thumpr cam is .513 Intake, .498 Exhaust and I think it sounds pretty good. I used the Comp Cams BeeHive valve springs on the stock heads and it turned out fine.

Here's a link to the car:

http://www.youtube.com/watch?v=LgYLtfebqss

 

[Shortbed70]

In a high rpm motor .100 is best but on a street driven motor .05 should be fine. You better have a good amount of compression for a cam that big and I hope your heads aren't some 1.94 valved head.. .575 is large for a 350-360" motor.

 

[84cutspreme]

pretty much all setup now, cam is .510/.520, 230/236 dur, heads are 64cc comb, 180cc int run, 2.02/1.6 and with the 1.6 rockers im gettin lift will be @.544/.554 and my springs are max lift @ .620 now. I should be fine and compression is somewhere around 9.6:1-9.8:1. full roller setup

little side note the thumper cam you have is a nice setup, I looked into the thumper line, but they are designed for sound. If you notice the usual setup has higher lift on the exhaust where the thumper has the higher lift on the intake.

 

[mebe007]

Honestly with that much can I would want more compression. You could bump it up more with a thinner head gasket. Did you get iron or aluminum heads. If you went the latter of the two I would Def bump the compression to make the best power. Remember aluminum heads like it hotter to make the power and get a complete burn. That's why iron heads see generally best on a low compression motor.

Also I notice you said full roller setup. You need to check the spring pressures as roller cans require more pressure than a flat tappet. Not something you want to overlook

 

[84cutspreme]

I did get aluminum heads, and yes I checked and they are the dual valve springs setup for a roller setup. I know I'm a little low on the compression. I was originally gonna keep 1.5 rockers and keep lift @ .510/.520, but my buddy talked me into it.

Only thing I am wondering now is what kind of oil I should use. I've been using rotella-t + zddplus because my cam at the moment has been flat tappet.

 

[mebe007]

That's the good thing with roller cams. You can run any oil you please. Mine is full of vr1 synthetic right now