331 or 347

[skinnystangman]

I have a set of SRP pistons. They have SRP 40F on the bottom side. Are they 331 or 347 piston? How can I tell other than the part #. Does anybody have a pic of the two?

[bobs94formula]

You'll probably need the part number. That may just stand for .040" Ford.

I'm just guessing I don't know for sure.

[Grape]

pin height will be .150" higher in the 347 pistons

[skinnystangman]

But if I don't know what I have then I can't really tell a difference. Thanks for trying to help grape.

[YALE]

Call SRP and ask for some direction. How did you end up with random pistons?

[strokin]

U take a pair of dial calipers and check the pin height, you will not need much else, if you dont have the part number then calling srp will not do much good.