I have a brand new set of Wiseco K506M815 pistons for the 4AGE later model with 20mm wrist pin. These are forged with compression ratio of around 10.5:1 if using the stock head gasket, and up to 11.8:1 with some head work done before they interfere with the valves. They will be perfect for all motor, or even a high compression turbo build (which will be extremely fast spool and broad power band). Wiseco pistons have been known to withstand anything you can throw at it.
Here are technical specs:
- 81.5mm bore (.5mm oversize)
- Coated rings and side skirt for high heat tolerance
- 20mm Pin
- Dome shape
Retail is around $500 at Summit: http://www.summitracing.com/parts/WIS-K506M815
My price is $350 picked up. It will come with Wiseco rings, pins, clips pre-installed. Still in original box. I'm located in Stone Mountain, GA. You can call or text: 678-559-9707