Perhaps a long shot. Im in the middle of a 66 HP Conv thoroughbred project and am in urgent need of a set of 8 NOS or nice OEM HP 289 pistons that are .020. If anyone has a set or leads on some please message me. I have an nos set of 8 std HP pistons I can trade if needed.
-Matt
Never heard of.020 OEM pistons.
Roy
Quote from: TA Coupe on November 10, 2025, 05:52:31 AMNever heard of.020 OEM pistons.
Roy
Interesting and following
I haven't seen any but I do see .020 and 0.030 NOS piston rings for sale on EB, so the pistons must also have been offered as service parts.
I was just schooled by our revered retired parts man. over sized pistons were not offered over .003 but over sized piston ring were. No oversized service pistons will limit my options but at least finding any originals can be ruled out.
Quote from: 21.04 on November 10, 2025, 03:28:41 PMI was just schooled by our revered retired parts man. over sized pistons were not offered over .003 but over sized piston ring were. No oversized service pistons will limit my options but at least finding any originals can be ruled out.
You could of course sleeve all 8 cylinders to standard and use your NOS standard pistons. I and many friends have had that done many times over the years as a insurance policy against overheating issues with excellent results. We use a machine shop that has done it hundreds of times before on race and street driven engines. Just a alternative if you don't want to use after market pistons.
That was our initial plan to use the standard pistons and sleeve the cylinders. We've contacted several well known machine shops and they are all refusing to sleeve 8 cylinders for risk of cracking the block. The block is the original VIN stamped block to the car. If it cracks, I would not be interested in continuing the thoroughbred project, not to mention the loss of value to the car. This not be an easy decision to make.
Quote from: Bob Gaines on November 10, 2025, 04:52:16 PMQuote from: 21.04 on November 10, 2025, 03:28:41 PMI was just schooled by our revered retired parts man. over sized pistons were not offered over .003 but over sized piston ring were. No oversized service pistons will limit my options but at least finding any originals can be ruled out.
You could of course sleeve all 8 cylinders to standard and use your NOS standard pistons. I and many friends have had that done many times over the years as a insurance policy against overheating issues with excellent results. We use a machine shop that has done it hundreds of times before on race and street driven engines. Just a alternative if you don't want to use after market pistons.
Should you do that, the structural integrity of the block will surely be compromised.
No bueno
FL SAAC
QuoteShould you do that, the structural integrity of the block will surely be compromised.
No bueno
Hmmm, thats an awful lot of engine blocks that are "compromised"
I believe all aluminum engines are sleeved as are many racing engines
Please seek professional advice.
Quote from: 21.04 on November 10, 2025, 11:14:59 PMThat was our initial plan to use the standard pistons and sleeve the cylinders. We've contacted several well known machine shops and they are all refusing to sleeve 8 cylinders for risk of cracking the block. The block is the original VIN stamped block to the car. If it cracks, I would not be interested in continuing the thoroughbred project, not to mention the loss of value to the car. This not be an easy decision to make.
Yes I have heard that before.That is why I use a machine shop that has done it hundreds of times. Of course the block has to be inspected thoroughly to confirm it is a viable candidate. I am talking from first hand experience like I said I and many others that I know have had it done successfully many times over the years. So I know it is a viable alternative. It s not for everyone and I understand your apprehension. I guess your stuck with using after market pistons then.
Thank you Mr Gaines, its good to have experts here
Quote from: Coralsnake on November 11, 2025, 09:55:47 AMThank you Mr Gaines, its good to have experts here
Thanks but not a expert on engine machining, however I do have practical experience on some things that have worked for me and others over the years.
Heres that pesky AI thingy 😂
Why Sleeve an Engine? | PowerBore Cylinder Sleeves
Yes, most high-performance racing engines are sleeved, as sleeves add durability and strength to the engine block's cylinders. They are used to handle extreme pressures and stress, allowing for greater horsepower and torque while preventing damage to the cylinders. Sleeves are often a necessary part of building and restoring performance engines.
New vehicles with aluminum blocks are... you guessed it...sleeved including Corvette.
Sorry the post was modified and locked after a member became disrespectful to others.
Having a different opinion is fine, but it should be done in a professional manner. Members that fail to follow to the guideline will have their posts deleted.