Mine isn't running yet. However, I have a couple of friends with the same engine, and saw one run on a chassis dyno. They run great.

Erik,

I guess checking would be OK, but it's the same combo Chevy put in the ZZ430, and they used the stock FB385 heads. Same with Scoggin Dickey. Their tech folks say the springs are fine, and the heads will take a .525 lift.

You can't put 1.6 rockers on the exhaust valves STOCK FB385 camshaft, though.