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Should I reuse stock pistons?

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Old Jul 20, 2018 | 11:28 AM
  #1  
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Should I reuse stock pistons?

I am doing my first build--a disassembled 455 I purchased off ebay. Came with 7 of the original pistons. They have a very shallow dished top, are considered high compression, approximately 10:1.

Should I buy one piston to complete this set, or buy a whole new set?

By the way, I intend to reuse the 8 rods it came with, unless someone on here enlightens me against it.

Thanks, Jack
Old Jul 20, 2018 | 11:35 AM
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The first question is, does it need bored?
Old Jul 20, 2018 | 11:43 AM
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I don't think so, but my shop will confirm that next week.
Assuming the bores are in spec, I'm wondering if it's acceptable to reuse original pistons, or whether it is wiser to use a new, more modern set.
One issue I read about had to do with the thickness of the rings used on older pistons. And that new pistons use thinner rings that work better.
Old Jul 20, 2018 | 12:01 PM
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New stronger pistons would be a good idea.
Old Jul 20, 2018 | 12:07 PM
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What are the expectations? If totally stock yes it's ok. If it is a performance build I'd go new.

Good luck!!!
Old Jul 20, 2018 | 12:25 PM
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Originally Posted by m371961
The first question is, does it need bored?
You mean does it need to be bored?

Otherwise, Patrick is correct -- don't make any decisions until you hear from the shop. Chances are, at the very least there will be cylinder ridges that you'll have to cope with.
Old Jul 20, 2018 | 01:16 PM
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Originally Posted by Sugar Bear
What are the expectations? If totally stock yes it's ok. If it is a performance build I'd go new.

Good luck!!!
Well, not quite stock. I am installing an Engle 18/20H cam (pn#27184), an Edelbrock Performer intake, and headers.
Old Jul 20, 2018 | 01:18 PM
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I'd appreciate recommendations on affordable pistons. Looking for at least 9.5:1 compression ratio.
Old Jul 20, 2018 | 10:42 PM
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If your builder says you can use them, 100.00 plus shipping



I'm having a 455 built and bought Pistons too soon. I bought speed pro standard Pistons. Your builder will determine what you need to get your compression ratio. It will depend on your heads too. If he says stock standard Pistons will work I have a brand new set still in the box.
Old Jul 20, 2018 | 11:08 PM
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Originally Posted by Gary M


I'm having a 455 built and bought Pistons too soon. I bought speed pro standard Pistons. Your builder will determine what you need to get your compression ratio. It will depend on your heads too. If he says stock standard Pistons will work I have a brand new set still in the box.
Sounds good, I'll let you know. I'm using C heads and the thinnest head gasket I can find. The 7 stock pistons I have look like they have a shallower dish than the ones you pictured here.
Old Jul 20, 2018 | 11:24 PM
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If your using stock heads he will probably suggest a flat top piston with valve reliefs. That's again depending on if it needs bored and the cc of the head. This time I went with Edelbrock heads that have a smaller chamber so the dished 30 over would work on mine. Definitely let him choose. I didn't and now I have standard Pistons I can't use. Good luck, the 455 is a torque monster.
Old Jul 23, 2018 | 09:04 AM
  #12  
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Originally Posted by Gary M


I'm having a 455 built and bought Pistons too soon. I bought speed pro standard Pistons. Your builder will determine what you need to get your compression ratio. It will depend on your heads too. If he says stock standard Pistons will work I have a brand new set still in the box.
Do you know the dish size on these pistons? Are these forged or cast? Seems to be different versions of this piston when I search the part number...
Thanks
Old Jul 23, 2018 | 10:44 AM
  #13  
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forged from Rocketracingperformance.com

Item #:
FDML2323FSpeed-Pro Power Forged Piston Oldsmobile 455 .Set of 8 Dish Top 4.125 in. Bore .AVAILABLE IN STD .030 .040 .060

Bore (in):4.125 in.

Bore (mm):104.775mm

Piston Style, Dish, with no valve reliefs

Piston Material:Forged aluminum

Compression Distance (in):1.735 in.

Piston Head Volume (cc):+18.00cc

Wrist Pin Style:Press-fit

Pin Diameter (in):0.980 in.

Piston Ring Thickness:5/64 in. x 5/64 in. x 3/16 in.

Quantity:Sold as a set of 8.

Notes:0.142 inch deep dish design. DurOshield® coated piston skirt

Old Jul 23, 2018 | 09:14 PM
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Originally Posted by Gary M
Item #:
FDML2323FSpeed-Pro Power Forged Piston Oldsmobile 455 .Set of 8 Dish Top 4.125 in. Bore .AVAILABLE IN STD .030 .040 .060

Bore (in):4.125 in.

Bore (mm):104.775mm

Piston Style, Dish, with no valve reliefs

Piston Material:Forged aluminum

Compression Distance (in):1.735 in.

Piston Head Volume (cc):+18.00cc

Wrist Pin Style:Press-fit

Pin Diameter (in):0.980 in.

Piston Ring Thickness:5/64 in. x 5/64 in. x 3/16 in.

Quantity:Sold as a set of 8.

Notes:0.142 inch deep dish design. DurOshield® coated piston skirt

Got it. Thanks much. Hope I can use these--should know later this week.
Old Jul 23, 2018 | 10:25 PM
  #15  
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No problem. The main thing is that you get what you need. The builder is the best one to advise you on that. cant wait to get my motor back. Good luck to both of us.
Old Jul 25, 2018 | 09:09 AM
  #16  
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Originally Posted by OLDSter Ralph
New stronger pistons would be a good idea.
I will need new .30 over pistons. Do you have a piston/rod recommendation? I'm looking for 9.5:1 compression to run 91 octane fuel.
Thanks
Old Jul 25, 2018 | 09:12 AM
  #17  
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Originally Posted by Gary M
No problem. The main thing is that you get what you need. The builder is the best one to advise you on that. cant wait to get my motor back. Good luck to both of us.
Well, bummer. I will need .30 over pistons. Thanks anyway!
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