I have a gen 5 454. iwent out to scavenge some parts and i did not have anything to measure the bore. However the pistons are domed pistons and have the numbers 687383 stamped in the top of them. if i had to guesstimate they would have about a 15cc dome. But any way is there someone here that could run this number for me and find out what pistons these are?

Dude, you gotta match pistons to the bores. If your pistons are 4.250 pistons, but your bores are worn too far or have taper in them, then it doesn't matter anymore...

A cheap set of 4"-5" mics is $50.
A decent set of telescoping gauges is $75.
Those are minimum requirements.

A used bore gauge is around $120.

OK i have 6 years in machining and another 13 in machinery erection, i know this, i am peddling everything i do not need. i know there are not factory pistons. a friend of mine wants them and i would like ot know what they are before i sell them to him.
I do not have access to a database to access these #'s.

hpy,

re-read your original post.
It sure reads like you were planning to match up a new set of pistons to your bores by ID'ing your existing pistons...