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Old 09-29-2002, 05:39 PM
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Post 9.0 or 9.5 compression

I have new crate 350 motor rated at 330 horsepower.It has a 268 extreme comp cam. I talked to comp cam rep.about better sounding cam with good bottom and mid range.I now have a special grind 226/230 .481/.481 with 107lsa/104.What advanage if any would bumping my compression to 9.5. This motor is in 1931 vicky with 411 gears and Barry Grant 625cfm. Any comments would be great appreciated. I have good running car but want big cam sound with good bottom and mid range.

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Old 09-29-2002, 06:05 PM
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With a light car such as a Model A and with 4.11.gears...... I do not understand all the concern for bottom end and mid range.

The good sound most folks relate to is a combination of compression (the pop) and a good bit of duration at .050 and 106 degree centerline does not hurt. Raise the compression to 9.8 or 10 with High test fuel.

I have a all steel FOMOCO Deuce roadster and the loss of bottom end power actually helps it not haze the tires. My engine is a GM issue ZZ430. 430 HP and 430 FT lbs. of torque. The Deuce weighs in at less than 2300 lbs. Had to go up on duration in the camshaft to kill bottom end and it helps a good bit overall.

Just a suggestion.
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Old 09-29-2002, 06:44 PM
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Do you have a true 9.0:1 compression ratio now? if you do, I wouldn't bother messing around for a half a point in compression. You'll never be able to tell by the seat of your pants. The cam your going to install should work well with your lightweight rod, and 4.11s. Besides, with the 9.0:1 engine, you'll have a little safety margin, because the fuel quality (octane ratings} seem to be on the decline these days.
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Old 10-04-2002, 07:44 PM
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yeah, I wouldn't worry about the compression ratio , you've already got a good set of vortec heads, if you've got that budget performance 350.
good call with the cam change, the old cam is .431/.460 with 206/212 duration if I remember correctly, with that cam youre probably in the 360-380 horse area, once you get it in the car. you'll see.
My dad and I put the same motor with the deluxe package in an 80' camaro. and it ran alright, we even fabbed up special brackets to run ac with the headers he bought. happy hot rodding!!!!!!!!!!!
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