Not to worry,
I've got a 509 400 blk, filled to the water pump opening and after i put it together and started filling the radiator, we discovered a 4 1/2" long crack about 3/4" below the deck. We decided to run it dry and made 11 passes on alcohol in the dragster.
We then pulled it out and before transferring it to my Malibu, i tig welded it with nirod using the hammer method (weld 1/4" hammer the weld, cool down and repeat), without even pulling the Alum. heads. I re-torqued the heads and put it in the Malibu, it now has over 100 passes without one flaw.
And i do get a lot of flap from some excellent engine builders for using stock blks, but this engine ran 5.16 and 8.23 in an 1850lb dragster while running dry.
Due to the too nasty cam it's down on torque and not enough gear for the heavy car (3253lbs) so it only runs 6.52 and 10.59 @124mph in the Malibu.
JMO
Zip.