how far can you safely bore a 60 block with out any problems

 

most will say 30 over but 60 is the max i have ever seen or heard of so 30 is ideal and gives room to rebuild in the future if needed

gary

 

Most can do .030.

I had a .060 setup but a minority of the blocks are there are capable of taking this much of an overbore due to core shift.

 

these would be iron (6 Liter) blocks right?

 

What is your intended use for the ironblock N/A or N20 or other form of F/I. If your staying N/A for sure 4.060 is the most you can go but YOU MUST SONIC TEST the block if you go .60 over as many are to thin to be taken out this much. The 4.060 give you 414 cid with a 4.00 crank. If you want to spray or go other form of forced induction then stick with 4.030 for plenty of strength and room for future rebuilds if necessary and this gives you 408 cid with 4.00 crank. This is the most common bore size (4.030) for a 6 liter iron motor from what i have seen. 4.040 bore would also work for most applications and give you 409 cubes!