How far can a 454 Mag be bored?

depends on whats left of the block.

Depends on what Gen and how thick the block is. The older MK4 could go bigger. Gen 5 & 6 are maxed at .060 and lot them can't even go that far.

some of the MK4 blocks are pretty done at .060 depending on the casting number and core shift. some are fine at .070 or so and the older 512 casting numbers are fine at .100 over if they dont have a core shift issue. seems like the later of the MK4 blocks were when they started getting thinner but not positive of that.

Thanks all it's a 98 motor and already at .060 I figured the block was probably done.

I ran a Gen V .070" over (4.320) for 13yrs up to 600HP at @ 6500 at a times with no issues. The engine was built at 420HP by someone else 6yrs prior to me. Not recommending it without the block being checked, but I have done it.

This motor would be around 800+ HP Just looking at an old project boat and adding the $$$ up. Ahhhh Toys!

The pin would be pulled... Lol

I can do that just adding up the cost and considering if I want to buy the boat.