409 pistons?

[Bungy]

I got a set of pistons in a W-parts pile deal and I'm not sure what they are. Can anyone identify them? The numbers on the bottom are 3819377. Are these 10:1 11:1? Std or oversize? They have one valve relief notch on the top. Also how can I tell if they are forged or cast?

[64ss409]

I don't see a 3819377 listed in the parts book. Could it be a 3819577? If so, it would be high performance 409, forged, std. pistons for cyls. 1-4-5-8. Do you have 4 others with a different number like 3819576?
Ron

[Bungy]

Thanx Ron, I only looked at one. Maybe it was a 5 insted of a 3. I'll have to check the others and double check that number.

[gearhead409]

i might learn something here but as far as i know all solid lifter 409s used a forged piston with #3819377 on the under side of them. don't make any differance on size or valve relief cuts. same forging.

[64ss409]

gearhead409 is correct. I just checked a few that came from a 400hp. They all had 3819377. Nothing to do with the numbers in the parts book.
Ron

[Ronnie Russell]

I can not understand how all can have the same casting no. 4 have intake reliefs on one side the other 4 are opposite. ?????????

[gearhead409]

the head of these pistons is very thick. on the under side there is no sign of the forging made for a dedicated area for valve reliefs. that's one of the reasons they weigh nearly two pounds each.

[Ronnie Russell]

Thanks gearhead. I think I see now . Forging numbers all the same. Then the forged blanks are cut for either right or left and given a part number.

[SteveD409]

There are CASTING numbers and there are PART numbers and they are not neccessarily the same on a part. What is cast into a part is not always the same number found in the parts book, though sometimes it is. :dunno And other times the casting number is given in the discription area of the parts book---is that clear enough? :)

SteveD

[64ss409]

Also how can I tell if they are forged or cast?If a piston has a steel plate visible on each side of the pin boss, it is a cast piston. It is cast into the piston for structural strength. Forged pistons do not have the plate. The photo is a 340 piston.

Are there cast pistons without the plate?? :dunno Someone else will have to answer that.
Ron

[Bungy]

Thanx for al the info guys. I checked the pisons again and they all have 3819377 except one. It has 3833461 and it is cast. :dunno So now my question is: Does anyone have a std bore 3819377 piston they want to get rid of?