Originally Posted by Viban
The guy at my shop said that this was the biggest I could go without that being necessary.
The .480" lift on exhaust is cutting it pretty close. There are a lot of variables in the production of cast heads and some have more or less clearance than others. You should have at least .060" between the valve retainer and valve seal at full lift. After reading your post, you never even verified clearance.
Also it doesn't appear that you replaced the stock springs with the proper springs for the cam. Stock L31 springs will go into coil bind around .420" lift. Furthemore, the stock springs lack the seat pressure to keep the roller tappets on the face of the cam lobes which means:
-.060" clearance between the retainer and seal may not be enough
-if a lifter jumps off the nose of the cam you have instant engine destruction
I suggest getting the correct springs and retainers and verifying clearances before you attempt to start the engine.
More info can be found here: http://www.crankshaftcoalition.com/w..._cylinder_head