Those will raise your compression rate and they have a thinner top ring and shorter skirt. I know. I have a new set if JE 4.5s here. But i went with the inverted dish. But the dish is too big

Would like to thank all that posted. You have helped me. Thanks!

The Merc part # you listed - 798-841233T1 is for the 575 SCi and is .034 oversize and yes that is correct it is NLA thru Merc. The standard bore piston for the same 575 Sci is still available. How dumb is that. Who needs a standard piston after tear down. Anyways retail thru Merc is 208 dollars for the standard size.

The domes / dish on the 500 EFI and the 575 SCi is totally different. Your post #8 from Summitracing piston is the same dish as the 575 SCi. I am not saying it is the exact same piston but the dish looks the same. The 500 EFI has valve reliefs.

Yeah and the piston in post 8 is not availible in anything but a 454 . The piston in the post # 7 is completly correct except the dish is wrong. It is also the only piston that had a 2 mm . 1.5 mm and 4 mm ring set like the ones in my motors. .


. You can buy a bowtie block cheaper than a standard 8.2 block. The bowtie block is way better. BUT it is 4.5 bore to start . So wth. I have to get a 8.2 block and then get the pistons form merc. They must be overstocked. But i would like the exact same thing i was running. ( with the longer reinforced skirts)

Do you know who has the OEM stock bore pistons. I can't find a set anywhere

I do not nor have them on the shelf and I doubt very much any Merc dealer in the world would either. To stock everything on the marine side it would take millions upon million of dollars to do so. If I had that kind of money I sure in the hell would never be in the marine business, I would be sleeping well everyday.

Anyways if you want me to check in with Merc I can but as you know their price is ouch to the consumer plus they only list the standard size pistons for the 575 SCi. Let me know and are you sure the pistons needed is what I posted by the Mercruiser part # in my last post.

Okay thank you. I am now looking for standard bore pistons. The Merc number is 849022T1. The pistons i have (that i am replacing)say 849022A1 the motor is a 575 sci. Stock pistons is what I need Thanks

What did you get anything. I did talk to Merc today and for some reason I have to give them a shout back tomorrow. Anyways Have you tried Ross pistons or Talked to J/E on the phone.

have not found a new set anywhere. And I don't want the J E aftermarket crap. I want OEM !! Thanks for your time