hemi piston id

need some help on a set of hemi pistons i aquired. i cleaned them up today so i can now post what i found. they are marked .030 over and 1 bank has the # 1757lp and the other bank has the same # but the l has a r stamped over top of it so it now reads 1757rp. also 1 bank, but i can't recall which 1, has what looks to be # p56713 but it has been stamped out with a rectangle of dots as to cross it out. i can post pictures if needed but the old dc catalogs and my trw catalogs and hensley's older sale catalogs didn't give me anything. also no dykes rings on these pistons. all help is appreciated! thanks, dave

What width ring grooves? A picture from the side showing the wrist pin will help identify them

cab: i took 3 pictures to post so i hope that will help. ring pack is 1/16 1/16 3/16. also i googled hemi pistons then hit images and they look alot like a set of trws that someone advertised on racing junk. also sorry about the poor pics and as always thanks for the help dave

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I would bet money that those are the TRW 12.5 to one pistons that Mopar use to offer The Speed Pro 13.5 to 1 compression pistons look a lot like these but the flat part on top is a lot narrower, like about a 1/4 inch wide, not a inch or more like yours If I remember correctly those are considered the SS 12.5 to 1 pistons for all the SS race hemi motors, NHRA use to use the dome height to the flat part as .750 above the decks The smart racers would buy the Speed Pros and massage the dome to get the most compreesion out of thier motors

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I would bet money that those are the TRW 12.5 to one pistons that Mopar use to offer The Speed Pro 13.5 to 1 compression pistons look a lot like these but the flat part on top is a lot narrower, like about a 1/4 inch wide, not a inch or more like yours If I remember correctly those are considered the SS 12.5 to 1 pistons for all the SS race hemi motors, NHRA use to use the dome height to the flat part as .750 above the decks The smart racers would buy the Speed Pros and massage the dome to get the most compreesion out of thier motors

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Cab, does NHRA still measure Hemis that way?