I run a 65 , 289 block on my 347 , no problems . I do use a stud girdle on the mains,makes me feel a little better.I run KB 13 to 1 pistons,672 solid roller.I did lose one 65 block but it was 060 over and split three cylinders after 4 years.I have built four 347's,all with 65-289 blocks. ROY
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