I'm deciding what cam to run in my 408. Running icon 10.5:1 dish top pistons. And ported magnum heads. Anybody have an idea of how much lift I can run before running into piston to valve clearance issues? The cam I want to run is .555/.576 lift. Just trying to avoid the headache of pulling it all back apart and cutting valve reliefs deeper

 

Get a DESKTOP DYNO,run some build spec's before spending money on parts.It will let your dream be real or give the real answer.Lots of spec's and choice of parts(not brands).It's cheaper than making paperwieghts with broken parts.

 

What is this? Never heard of such thing

 

That's right around the limit on stock bottom end. Hate to say but you're gonna have to assemble it and measure it.

 

You need to get out more.Lots of engine builders are using this concept in todays HP builds,There are many on-line programs for suggestions and fact for you to concider.Just a thought...........

 

Uhhh, this is a custom build with higher compression on a production block with loose tolerances compared to modern engines or race engines. To do it right you need to measure it. Assembled. Programs are great to see what kind of power you might put down.

 

What valve springs are you using?
Watch you coil bind, magnum heads don't allow much lift.

 

I'm getting the spring seats cut down to accommodate the .750 coil bind springs.