BBC 4.61 bore with boost

I know it's not a great idea, but how much power have people made? Seems like at least a few procharger motors are big bore? My mls gaskets looked pretty rough this time, but they were a couple seasons old and got beat up with nitrous before bolting this 14-71 on top. So, how much boost/power have you made with 4.600 or bigger bore and mls or oring?

 

We have a customer who runs a procharger, he tells us it has 42lbs boost. The original engine we built him had a 4.600 bore Dart Big M Block. The problem with the 4.600" bore was that the cylinders would crack at the center bolt holes from the top to about 1.250" down. After going threw a few blocks, we then had Dart make a compacted graphite block and went to a 4.500" bore, no more cracks and the customer went faster.

JP

 

4.6 bore

we are running 4.6" bore on a dart bigM with SCE integrated O ring gaskets, only 30psi boost but no problems for 2 seasons