Rv 440 + 6-71 ?!?

I am wondering how you know they are cast pistons?? The 413 that my Pops has in his Duster is from a Motorhome and it has forged dish pistons AND a forged crank! IIRC the comp ratio is like 7.8:1. The pistons have a large hole with a nipple in the center. First time I seen pistons like them. The pistons are .090 down the hole too!

Also wondering if the 6-71 is big enough. My buddy has a 440 with a 8-71, its a monster!

Just askn'!!