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Old 03-10-2011, 01:36 PM
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Cliff R Cliff R is offline
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Join Date: Nov 2000
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Compression is important in power (torque) production. Once you get past mind-set that a "perverbial brick wall" of 9.5 to 1 exists for these engines on pump gas,, the engine builder can use the compression to get these engines to manage larger cams.

The problem with this line of thinking, is that you can lower the compression and still manage the same cam. The larger cam takes a LOT of "wind" out of the lower compression engine, specifically down in the "normal" driving range, low rpms and at idle.

If you drop out a half point or so compression, to get the engine to run compariably to the higher compression one, at the same cid, reduce the cam duration by about 10 degrees.

In other words, a cam down around 214/224/112 would have been a better choice all the way around......Cliff

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73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile),