Quote:
Originally Posted by Tom Cimino
Or, if you want 427 ci, you can use your 352 block, bore it .060 and stroke it to 4.125.
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If the 390 block can be cleaned up at a 0.010" over bore, you can do the same thing.
Also be aware that there were a few 390 blocks that were cast with very thick cylinder walls. These can be over bored 0.080" to 4.130 which is the 428 cid bore. I have heard they were more commonly found in trucks - I don't know if that is true. If you do find such a block, you want to have the wall thickness measured carefully in all cylinders. One thin spot and you could ruin the block and you still owe the shop for the work done. If something bad happens, it will happen on the last cylinder.
There is an allen wrench test with a freeze plug pulled, that helps identify the thick walled blocks. If a certain size wrench will not fit between cylinders, then the walls are thick. That still does not assure it can be bored that far. Cores can shift and there can be thin spots. The bad news is these blocks are very rare to find now.