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More Radical CIH Performance Ideas by Jeff (Speedway GT) Denton...

1980 Views 5 Replies 4 Participants Last post by  GTJIM (R.I.P.)
I was just out in the shop studying a future Speedway engine block (thick main webs next time, thank you Darrin "Rallye 73") and I had a profound revelation. To be legal (minimum cleanup cut on the deck) and get Bob's .005 piston "stick-up" all I have to do is move the crank up, what, .025", right? The rules don't say anything about making a little mistake when line boring the mains...
So I might have to shim the distributor up a bit to prevent gear slop, and re-align the bellhousing, so what? I wonder if the front and rear seals would mind this wild modification. Maybe they could move up a bit, too.
"Don't raise the bridge, lower the river" almost fits this idea...
Also, were the deck "cleaned up" at just a slight angle, (cut a bit more on the right side than the left) it would improve any flame propagation interference that the closer piston to head quench area might create.
Then angle milling the head (cut a bit more from the chamber side than the quench side) would probably create the maximum compression ratio possible using stock parts. Could there be any other "tricks" I've not seen yet?
I wish Smokey was still around, he'd like this one.
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Sure, Dave, that is called stroking. It's the oldest trick in the book, the one that appears first in the rulebooks practically everywhere as being not allowed. The racetracks have a tool they use a lot, a big plastic air cylinder with a piston that floats up and down. They "pump" our engines with it, it tells them the volume of the cylinder and thus the cubic inch displacement of the engine. Their results better match the displacement posted on the lower right corner of the windshield and it better be a stock, factory displacement!
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