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Can anyone identify the type of piston this is? Compression ratio, 10.5-1?
When I bought the 60, it came with this "spare" engine. It has been decked but not rebored. I am not sure of the cam. I will spin it over later this week.
I looked at your ideas and I see some differences. The picture is hard to see, but there is a concave indent where as the 327/350 stock piston or speed pro L2166F has a higher spot.
It's a domed piston. Can't tell you who made it. It's a 283 not a 327 but the pistons look just like 327 factory pistons except they were forged. I believe yours are cast. I can't think of any reason in the world why someone would put dished pistons in a 283.
Here is a standard size GM NOS 283 high domed fuelie piston. I found 2 a few years ago. I ended up sleeving my '59 283 fuelie to bring her back to std size and had a set of custom dome pistons made to keep the 10.5:1 compression ratio.
Last edited by Jake Morgan; Feb 10, 2021 at 06:18 AM.
Before we started we put together a game plan...measured the deck height and amount that would need to be removed to produce a flat surface. We also looked for a specific head gasket with an acceptable thickness that would achieve our outcome. The sleeves themselves where installed with a little left above the deck plane, which was removed as the block itself was decked.
I'm doing the same with my '58 283 with a dual quad.
Here is a picture of the custom piston...a little more valve relieve which is compensated with a bit higher dome; has plenty of clearance all around installed.
I need to apologize to all those that stepped up to help me out. I am VERY new at this and truly did not understand what I was looking at in the piston. It is domed, as you all knew. The newbie goofed up. I appreciate the help and will try to get a better understanding before I post for help. Thank you.
I believe the first use of a domed piston was the '57 283 HP FI engine, and this piston continued with the 290 HP FI engine through 1960. These engines had a advertised CR of 10.5:1. For '61 I believe a slightly different design with a larger dome was used on both the 275 and 315 HP FI engines with the new 461X heads that have slightly larger chamber volume than previous heads, and the advertised CR was increased to 11:1
My understanding is that these pistons were cast and being as how they were for the 283 the nominal skirt diameter would be 3 7/8" versus 4" for the 327. I recall a repro outfit, Danchuck, that specializes in full size Chevrolet repro parts offers at least one of these pistons, but I don't know who manufactures them.
The first use by Chevrolet of forged pistons was the '62 340/360 HP 327s.
Here is a picture of the pistons I had made for my 57 - 283" with a 283HP FI engine. The manufacture needed the 539 pyramid heads as well as the cam (097) lift info to mock these pistons up with. I believe they got it right as the mighty little 283 runs well... Al
Piston type
