Just a note here for anybody putting together their own motor.
I bought these pistons as part of a stroker kit. It came with the rods, crank and pistons. With a combustion chamber size of 64 cc's (which is what the heads I have are), it's supposed to be a 10:1 compression ratio.

One evening I was sitting around running all the componet numbers through a nifty compression ratio calculator I had, and low and behold it kept coming out 8.4:1 ?
I'd thought from the beginning the dish in these pistons was awfully big and deep to come out at 10:1 ? but who am I to question the speed shop that put this stroker kit together, and has been in business for many many years ?

Turns out it's a good thing I did question it, because after running it a couple more times with the same result, I took the specs to a couple of people who have been doing this for a long time. Guess what ... they came out with the same thing I did !! 8.4:1 ... Not good !!  I gathered all my info up and went back to the place I bought the kit, and they casually went, "oh, I'll be darn, you're right"
They then proceeded to give me another set of pistons with a much smaller dish than the one's in this picture, and then walked away like it was no big deal.

How many people have bought this kit and wondered why it just never ran like they thought it should ? How many people are still to this day running around with an 8.4:1 compression ratio, and think it's 10:1 ??
Was it an honest mistake, or did they do it on purpose, thinking they would get much fewer returns for broken parts, if they secretly snuck an 8.4:1 compression ratio on you instead of a 10:1 ? I don't know the answer to that question, but I do know they seemed very unconcerned about it when i brought it to their attention!! They simply handed me a new set of pistons, smiled and went on about their business.
My guess is they knew it was the wrong pistons and they have been selling it that way from the beginning.

The moral to this story is, don't trust anybody, it's easy to make mistakes, or just get conned. Check and recheck everything yourself !