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By Jack Groat - 6 Years Ago
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First, I would like to say that of all the websites I have posted my hot-rodder (and other) questions, this site is the best. Guys who are really knowledgeable come up with some really good answers.
That being said, here are my latest questions. I have a junkyard 292 from a '61 that I am in the process of rebuilding. The block has not yet gone to the machine shop. I did NOT get the piston to deck clearance upon tear-down. I guess I could do a quick reassemble to get the answer, but this is easier.
1) Does anyone have a good guess as to what the stock piston to deck clearance distance is?
2) If I choose to do some deck milling to adjust my compression ratio, what is the minimum I should use?
Thanks guys..
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By Ted - 6 Years Ago
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Stock piston to deck clearance was in the neighborhood of 0.025”-0.030”. If going with composition head gaskets rather than the stock steel shim head gaskets, then target for zero piston clearance to the block deck with the new pistons. Keep in mind that most replacement and/or oversize pistons have the wrist pin closer to the top of the piston which in turn puts the piston even further down in the hole than the original stock pistons. Add to this is the rod length which shortens up some when resizing takes place. With all this in mind, then you may end up cutting the decks as much as 0.045” (or more) to get to the zero deck measurement. If using steel shim head gaskets, then target for at least 0.015” in the hole.
With all that said, it’s best to dry assemble the short block with the rods and pistons being used and measure the deck clearance at the four corners and machine the decks accordingly. If you arbitrarily just machine the decks without doing the aforementioned corner measuring, you’ll likely not be the same on both banks. It’s also not unusual for the decks to be higher on the diagonal corners than on the other two corners. If resizing the connecting rod big ends, then measure all to insure that they are consistent in lengths.
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By Jack Groat - 6 Years Ago
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Thanks Ted...
By the way, do you have a y-block in that "Altered T" you show in you signature?
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By Dave C - 6 Years Ago
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Yes he does.. Ted has several Y Block powered toys at his place. I sent several enjoyable hours with Ted a couple of weeks ago and he showed all of them to me. Interesting day to say the least. Usually when I see Ted it is to get a rotating assembly balanced, so I just drop it off and go over what I want done. For some reason this day we had lunch and spent time BSing. Good times.. Dave Jack Groat (12/11/2018)
Thanks Ted... By the way, do you have a y-block in that "Altered T" you show in you signature?
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By charliemccraney - 6 Years Ago
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A couple vids with it.
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By Ted - 6 Years Ago
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Jack Groat (12/11/2018)
Thanks Ted... By the way, do you have a y-block in that "Altered T" you show in you signature?
As Dave and Charlie mentions, I do have a Y in a Altered Roadster. Single four barrel with a vacuum secondary carb just to prove a point. Here’s a video of it running at the local track. Crowd sort of goes wild when a Y takes out all the Big Block GM powered entries.
https://www.youtube.com/watch?v=PASdMy0mkwY
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By Brent - 6 Years Ago
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I'm INSPIRED!!!
THANKS CHARLIE &TED!
My 1955 Thunderbird body is almost done. 113's are going out for finish work, crank is at the shop and, damn that's a bunch of awesome cars. I hope to play, SOON.
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