Have you tried doing a search ? That should answer your question. I remember this being discussed several times before.
It can be done to some, good idea to sonic test the prospective block. The 425 was cast with larger cylinder holes.
The people who have succesfully had one bored that far will tell you go for it. The ones who tried and hit the water jacket will tell you otherwise. I would call it a 50/50 shot. To avoid the cost of sleeving it or sonic testing, I would go with 30 thousand and enjoy.
I agree with Doug. The difference in power isn't so great so as to justify taking such a huge chance on ruining a good block. What happens if you get it all finished and later discover an overheating problem caused from thin cylinder walls? Not too pretty.:bglasses:
