Bozang1

Anyone have a pic showing the high compression piston for a 455 vs a low compression piston for the same motor? I might have an opportunity to get brand new high compression pistons (stock bore) with reconditioned rods (I gotta ask him to clarify exactly what he means by that) for trade for something I have. Don't have time to post the pic he sent to me but they have a large dish in the top. I thought those were the low comp pistons??? Or do they both have the dish, one just deeper than the other?

svnt442

That all depends on what pistons they are. I would be HIGHLY suspect if he claims that they are factory high compression pistons.

Bozang1

Here's a pic (I hope)

Bozang1

Yes, doesn't look brand new. These have been sitting for years. Guy used to be big into Oldsmobiles and has a lot of stuff but he's in the process of moving...

MDchanic

Someone else here will be able to tell you what that piston IS, but I can tell you that it ISN'T a factory piston, and that, from that angle at least, the dish looks too deep to be "high compression."

If you measure the depth and diameter of the dish, you can figure out what compression it will give you with a given set of heads, deck height, and head gasket.

- Eric

pogo69

The pic is not super clear to me on my phone but they look like a HC piston...at least they look like the HC pistons i have in my engine...both high and low comp pistons like that sre dished..sorry i cant be definitive on my crappy phone

tru-blue 442

Here is a pic of a factory h/c piston from a 70 442 455.
Note the V notch. They are dished, but not a much as the l/c.

Paladin31

I realize you asked for 455 piston pic's, all I can offer is this one, 69 400 W-30 piston, hope this helps you


Brett

Magna86

Those are low compression pistons. Dish is way too deep. The pic Bozang posted. Others definitely high compression factory.

Paladin31

Whose pics are you referring to?

pogo69

The 400 pistons look like factory HC ones