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It kind of depends on which FE block you get. Some, like the FT and the mirror 105 type blocks, will take a bigger overbore than standard 390 blocks. The mirror 105 blocks are usually found as later (1970's) 360 engines, in pickup trucks. In any case, with any overbore over .060", have it sonic checked.
We get a lot of people on here wanting to build a maximum cubic inch FE. I can appreciate that, but overboring is not the way to do it. You get minimal gains and take a lot of life out of a perfectly good block. Overboring should be reserved to cleaning up cylinder walls. If you want cubic inches, switch to a bigger crank.
It kind of depends on which FE block you get. Some, like the FT and the mirror 105 type blocks, will take a bigger overbore than standard 390 blocks. The mirror 105 blocks are usually found as later (1970's) 360 engines, in pickup trucks. In any case, with any overbore over .060", have it sonic checked.
We get a lot of people on here wanting to build a maximum cubic inch FE. I can appreciate that, but overboring is not the way to do it. You get minimal gains and take a lot of life out of a perfectly good block. Overboring should be reserved to cleaning up cylinder walls. If you want cubic inches, switch to a bigger crank.