cam for flat tops with no valve reliefs

The easy way is to install the cam you want and rotate it around the engine with clay ontop of the pistons.

Also realize that a Hyd. cams lifters are not pumped up when you do this. Grab 2 solid lifters and use them on checking this clearance. Proper pushrod length is needed.

I beileve others here said they use a purple 292/.509 without problems. I'd wait for a been there and done that myself.