cracked block

[Doug]

Looking for the cause for block cracking between bolt and cylinder on number 6 goes down .5 inch on 2nd row of bolts. Is on dart big m has happened on 3 motors need to find cause of problem. Motor is a 572 olds big chief blown alky motor. 4.5 bore

thank you

[Dart331stroker]

Is there anything else done weird to the blocks? Supports, brackets, things that may have not been part of the block when made? I only ask as we are working with an engine builder who ran across this as well, and we want to make sure we are duplicating the same information. If it is the same guy, we highly suggested changing the program to a Compacted Graphite Block. The engine builder we are dealing with has had Bow Tie blocks fail, Dart blocks fail etc. Not just a Dart issue. The area mentioned is all Iron all the way down to the mains. Plenty of material there, bores have over .275 wall at 4.625 bore. So it is not a material issue. They are iron blocks, ridged and strong, however no invincible, billet aluminum, Compacted Graphite Iron is more than likely the answer. We would highly suggest this, as the modfications being done to the mains etc, would not be necessary when doing the compacted graphite negating the additional cost expense.

Thanks
John

[Awesome Bill]

If it is the head bolt you are talking about running from the hole to the cylinder. Like the 400 sbc problem of cracking?