427 piston question

I've got a set of pistons with 7011p stamped on the top. I've looked online and asked around but i can't find any info on them (maker, age, material). I'm guessing they are forged judging by the dome top. Does anyone have an idea what they are?

look like old every day forged pistons trw was a supplier for raw forging for many . manley and speed pro . diamond so that number could be manley

Easier to tell if forged by looking at the inside, there are inserts in the casting that add structural support to the skirts on a cast piston.

forged you can see how the alum flowed out when forged and will be very smooth on the inside .yes some cast pistons have steel struts in them but as not allway a give away not the case as some of the mahle cast are very heavy round the pin . cast pistons ..look cast. if you look in the inside you can see lines from molds and not smooth

Thanks for the replies. forged, judging from the skirt. I'll look at Manley and the others a little harder for more info. Thanks again!

it may be hard to find under manley as that a older piston . you could try to call them or find a older catalog . i will see if i have one with them numbers in it

Thanks for all the help. I've been a silent observer of the website from time to time and have learned a few things that way. It's good to have this forum of knowledge that I can draw from. I'll bet a lot of people feel the same.

Speed Pro according to "Big-Block Chevy Performance" by Dave Emanuel. HP Books 1995 page 16. A book from my bookcase. I should have looked there before starting this thread. Also, upon taking the rod off and cleaning up the underside, TRW is forged (not stamped) into the piston. So, I'd say I have a pre-'95 forged Speed-Pro piston (as per the above book) from a TRW raw forging (as per Pat McCarthy).

well thats ok... i just think that the book got it right:HMMM:funny he did not call me when he writing his book:LOL: