273 pistons

[Rocky_JS]

factory slugs what are the difference between the 2 and 4 bbl? It is hard to see in the cyl even with a bore scope, but what I can see is the piston direction notch and 2 valve notches and can not tell if it has a slight dome. Don't the 2-bbl pistons have 4 valve notches?
I did search the forum but didn't really find what I was looking for?

 

[Abodybomber]

4 barrel"Commando: pistons,have a slight dome(110 to 125 tall) to them. 2 barrel pistons,flat tops.

 

[zhandfull]

This is a 4 barrel piston. It would be hard to tell the difference with a scope. As you can see from the side this piston has a raised dome to it along with a probably a shorter pin height. The 2 barrel would be a flat top piston.

Some of the aftermarket pistons I've seen have 4 valve notches. I'm not sure about factory low compression pistons.

 

[Rocky_JS]

Thanks for the replies and understood - the 4-bbl pistons because of the dome are one side only. I can not see a dome with bore scope.
While the flat top "IF" with 4 fly cuts are universal left or right. That is what I am trying to discern.

 

[66fs]

273 "4 barrel pistons" have 2 valve notches, and a dome. The pin is in the same position for either piston, except the 68-69 engines the compression height was raised to compensate for the open chambered heads. . "2 barrel pistons" have 4 valve notches, flat top, and a realy heavy pin to weigh as much as a 318 piston. "4 barrel pistons" typically ping with pump premium and a good quick curve distributor.

 

[Rocky_JS]

Thank you, that is what I wanted to know! It is a HiPo motor....