also keep in mind that some of the earlier blocks had piston rings that measured in MM so a 1/16 1/16 3/16 might not be a option but replacing them with a gm ring set..

R10575 502
(4.466 Bore) Plasma Moly Top Ring 2mm 1.5mm 4mm Std. .005
R10451 454 Special Race Blocks
(4.500 Bore) Plasma Moly Top Ring 1/16 1/16 3/16 Std. .005, .035
R10317 454 Special Race Blocks
(4.500 Bore) Plasma Moly Top Ring 1/16 1/16 3/16 Low .005, .035
R10595 454 Special Race Blocks
(4.500 Bore) Plasma Moly Top Ring 1/16 1/16 3/16 Std. Std.
R10452 454 Special Race Blocks
(4.500 Bore) Plasma Moly Top Ring .043 1/16 3/16 Std. .005
R10316 454 Special Race Blocks
(4.500 Bore) Plasma Moly Top Ring .043 1/16 3/16 Low .005, .035

So the cylinders have been bored, before the choice of ring styles were chosen?

The 177 is too small for a 502. You can make it work, but its not doing a whole lot besides making heat, but it can work.

I had it honed when I took it in for cleaning, etc.....

Fixx - some of the early gen VI? Of some of the MKIV?

I may have missed it, what r the pistons JE-700 ?

Yes

from what i remember if it was a je piston i believe all of them were metric size thickness..call je and ask..speedpro R-10575 i believe is the ring to use..also call speedpro and ask..its been a while since i have build a standard bore 502 engine ..

I just rebuilt a 3 year old gen VI 502 last spring. It had the metric ring pack. You will very few choices. I opted to go with the replacement pistons that weigh the same and accept a standard ring pack. This also fixed the oil blow by and oil consumption when used with the metric ring pack.