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]

Bungy

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]

Ronnie

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. And other times the casting number is given in the discription area of the parts book---is that clear enough?

SteveD

 

[64ss409]

Cast Piston

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?? 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. So now my question is: Does anyone have a std bore 3819377 piston they want to get rid of?