Thanks for the replies. That's what I'm after, Jerry. Originally, I was thinking it would measure from the center of the pin but wasn't sure I could get an accurate measurement. Shouldn't be hard to measure from the top of the pin bore to top of the pistons with calipers then add 0.4635" (half the pin dia.). Right now I'm exploring ways I might be able to get from 8.5 to a 9.5 compression ratio to optimize the cam I would like to use. May not be much to gain with different pistons where the standard is a flat top. Some of the pistons I've seen listed claimed to fit 153, 230 and 283 cid. engines, but didn't list a compression distance. Others listed for a 283 show compression distance from 1.780" to 1.800". I really need to find a book or other source with more detailed specs to make this a little easier to figure out. Maybe the way to go would be to look at the stroke end of the equation. I noticed the pre-68 250 has the same journal sizes as the 230 but with 0.280" longer stroke. If a 250 crank could be made to work, I could get there using flat tops.