350 Olds Question

[TeezySupreme]

I have dish pistons but i'm going with forged aluminum ones.

What kind of forged aluminum ones? Dish/flat/dome? Forged aluminum is just the material they are made of.

Flat my bad forgot to mention that 😀 .

 

[olds307 and 403]

I vote on the Probe flat top, actually 3 cc valve reliefs. Light and a thin ring pack, not much more than the Speed Pro's. Balancing and cam degreeing are good ideas. Those with a clean up mill on your #8's will give you right around 9 to 1. Don't forget a 3 angle valve job. Get them to use a bowl hog on the exhaust bowls and pocket port wouldn't hurt. The exhaust side needs the most work. Then you have more cam choices than 8 to 1 or less.

 

[TeezySupreme]

I vote on the Probe flat top, actually 3 cc valve reliefs. Light and a thin ring pack, not much more than the Speed Pro's. Balancing and cam degreeing are good ideas. Those with a clean up mill on your #8's will give you right around 9 to 1. Don't forget a 3 angle valve job. Get them to use a bowl hog on the exhaust bowls and pocket port wouldn't hurt. The exhaust side needs the most work. Then you have more cam choices than 8 to 1 or less.

What's make's these piston's better i was never recommended these?

 

[olds307 and 403]

They are the 2618 material, which is stronger. They have the thin ring packs, supposedly less friction and actually better ring seal. They also weigh less than the Speed Pro's, have a taller compression height(less decking for 0 deck) and can be run actually tighter despite the material differences. The Speed Pro's are a strong but dated design.

 

[TeezySupreme]

They are the 2618 material, which is stronger. They have the thin ring packs, supposedly less friction and actually better ring seal. They also weigh less than the Speed Pro's, have a taller compression height(less decking for 0 deck) and can be run actually tighter despite the material differences. The Speed Pro's are a strong but dated design.

Ok Ok, i get it now so what rings would you use on these?

 

[TeezySupreme]

The compression cal say with the speedpro compression would be 11: 5 ..

 

[DoubleV]

The compression cal say with the speedpro compression would be 11: 5 ..

What were the exact numbers you used to come up with that?

 

[TeezySupreme]

The compression cal say with the speedpro compression would be 11: 5 ..

What were the exact numbers you used to come up with that?[/quote

I re did it and got 9:27


Bore: (diameter) 4.087
Stroke: 86 mm
Cylinder Head Volume: 80

Effective Dome Volume: -0
Use (-) for Dome and (+) for Dish.

Deck Clearance: 0
Compressed Gasket Thickness: 0.038
Number of Cylinders: 8
Compression Ratio : 9.27 : 1
Total Displacement (in.3) : 355.79
Total Displacement cc's : 5832.62

 

[TeezySupreme]

The compression cal say with the speedpro compression would be 11: 5 ..

What were the exact numbers you used to come up with that?[/quote

I re did it and got 9:27


Bore: (diameter) 4.087
Stroke: 86 mm
Cylinder Head Volume: 80

Effective Dome Volume: -0
Use (-) for Dome and (+) for Dish.

Deck Clearance: 0
Compressed Gasket Thickness: 0.038
Number of Cylinders: 8
Compression Ratio : 9.27 : 1
Total Displacement (in.3) : 355.79
Total Displacement cc's : 5832.62

I have no idea if that's write but i researched for all the stroke and deck numbers.

 

[olds307 and 403]

Probe should have rings for those. That number sounds close.