Engine block question.......?

[Glenn Briglio]

Originally Posted by Greg Reimer 7376

Got a big block Chevy bare block, needs cleaning, kinda dirty, block number on back is 3969854.One part number decoder says 1969-1972 402. I took a cast crank out of it, it was a 3.76 stroke 402. One of our local big block Stock racers wound up with that, but the same decoder shows that same casting number as going with a 454 truck engine,70-73 vintage. Is this some kind of thick walled block for the 402 that could be decently sized out to 4.250" or is this a thin wall 402 block? The stamping on the passenger side deck surface in front of the right head says T 1118 TBG which indicated a 70 402 truck engine,310 horse. Any big block authorities think this might be some kind of thick-walled block that could go 4.250" bore size? Thanks in advance.

If in question on cylinder wall thickness get it sonic checked. And yes it’s a 402 casting. Too thin