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Old 03-01-2010, 10:46 PM
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right cam size and setup

i have a 350 with 1965 double hump 327 corvette heads. not sure the compression, i have a edelbrock torker single plane intake not to sure about that, go with single or dual plan. the carb is a 750 carter. i am thinking about putting a comp magnum cam kit 480/480 lift. the motor is going to be installed in 1979 z28. the car has the original close ratio munice 4 speed with a 3.73 rear end, i was mainly wanting to know if that cam size will be a good combination with my set up. the rpm range is 2,000-6,000 which sounds good considering around 40mph the car is tacking around 2,000 in 4th gear not to sure because the speedometer is broke, i can easily cruise at 35mph in 4th gear. i'm also going to install roller rockers.

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Old 03-01-2010, 10:51 PM
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You have to know the exact static compression ratio before you can intelligently choose a camshaft for a motor. Call up any cam grinder, that's the first thing they want to know before they offer a recommendation on a cam for your motor.

In order to figure the static compression ratio (SCR), you need 5 values:
1. cylinder volume in cc's
2. combustion chamber volume in cc's
3. piston crown volume in cc's (and also whether its flat, dished or domed) If it is a domed piston, subtract the dome volume from the combustion chamber volume.
4. piston deck height volume in cc's
5. head gasket volume in cc's

Add 1 through 5 together and write it down.
Add 2 through 5 together and write it down.
Divide the larger number by the smaller number. That's the SCR of the motor.

Last edited by techinspector1; 03-01-2010 at 10:57 PM.
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Old 03-01-2010, 11:37 PM
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cam size

yeah i am a rookie at building a engine i'm only 20 years old. ive had the car since i was 10, it has a brand new gm crate motor with 260hp with headers and a 4 barrel, but it doent have headers and the 4barrel doesnt kick in do to linkage i think but its really slow. i bought another motor last year and i really dont know anything about it. besides the heads, intake, and carb i know the combustion chamber are 62cc, i dont even know what the combustion chamers are, all i know the lower the number is higher the compression is. the problem is right now it is a complete motor and i know it runs, i know it was just recently built. i should probably just leave it the way it is, but i want that cam sound and power. i know the guy that built it but i cant get ahold of him. for all i know it could already have a decent size cam in it

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Old 03-02-2010, 01:21 AM
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Practically all of us on this board have been 20 and a rookie. We had to learn or move on to some other vocation/sport.

You'll likely tear into the motor at some point for curiosity if for no other reason. Learn how to degree the camshaft for starters.
http://www.iskycams.com/camshaft.php
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Old 03-02-2010, 08:30 AM
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a 350 with those old heads (62 to 64cc) should have at least 9.25:1 cr. which is enough to handle a compcam 280h. (280/280 advertised, 230/230 at 0.050", 0.480" lift, 110 lsa).

make sure to run the right valve springs.

and use an oil additive like www.zddpus.com with that new cam.

your cam selection is good for a 4 spd and 3.73 gear.

I would use an edelbrock RPM intake. not the air gap, just the regular rpm intake. most likely will need a "drop down" air filter to clear the hood.

that cam will need 20 degrees of timing at idle. Total mechanical timing should be in the 38 to 40 degree range. Then add another 10 with the vacuum advance (get an adjustable vacuum advance canister) and plug the advance into a manifold source. So should idle at 30 degrees (20 mechanical plus 10 vacuum advance).
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Old 03-02-2010, 10:59 AM
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If the motor is hard to start with that much ignition lead, do this....

Interrupt the feed line to the coil and connect a momentary push button switch that cuts the current to the coil while the button is pushed in. Mount it so that you can operate the key switch with one hand and the momentary switch with the other hand.

To start the motor, press and hold the momentary switch while you turn the starter switch with the other hand. When the motor is spinning, release the momentary switch and the motor will fire off.
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