need cam suggestions
Thread Starter
Pro
Joined: Dec 2006
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From: wilmington nc
need cam suggestions
I need to decied what cam i want to run so i can check piston to valve clearence, then i would know how much i will be able to take off my deck. My combo is as follows 350 .030 over, dart pro 1 alum heads, 180 runners 72cc chambers, edelbrock performer intake, 600 holley, trw .125 dome pistons, 1 3/4 headers, aiming for 10.5:1 comp. Car has a munci close ratio 4 speed with 355 gears. Comp cams recommended 12-250-3 thats the xe284h 507/510 lift 240 dur. What do you think?
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
aim for a 10.0 comp. and go down on duration, 240 at.050 in
a 350 is to much unless all you want is midrange and upper
end power with nothing on the bottom for torque. you have a
performer intake and small 600 cfm carb well suited to a lower
rpm engine. As an example a crane hydraulic cam with 240 at
.050 intake dur. is showing a power range of 3200 to 6800 rpm.
a 350 is to much unless all you want is midrange and upper
end power with nothing on the bottom for torque. you have a
performer intake and small 600 cfm carb well suited to a lower
rpm engine. As an example a crane hydraulic cam with 240 at
.050 intake dur. is showing a power range of 3200 to 6800 rpm.
Last edited by Little Mouse; Feb 10, 2007 at 03:42 PM.
Burning Brakes
Joined: Aug 2006
Posts: 1,155
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From: San Diego California
You have a really nice engine. .I agree that Comp seems to be recommending a little too much cam. I would step down the duration and lift a little for your combination, especially for the street.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
If you have H618+30 pistons they have 1.560"cd & +3.5cc dv. Cut about 0.011" from deck to yield deck height of 9.014" (0.014" down in hole) ... use a Victor 5746 composition gasket (4.1"x0.026"x5.4cc) ... w/72cc chambers that'll make 10.47:1scr w/ great 0.040" quench.
Then pick the appropriate lobe.
http://www.21cgt.com/FMWebCatalog/frmConversion4.aspx
Then pick the appropriate lobe.
http://www.21cgt.com/FMWebCatalog/frmConversion4.aspx
Thread Starter
Pro
Joined: Dec 2006
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From: wilmington nc
I was just concerned with havng my deck cut and then finding out i don"t have valve to piston clearance i need, that would force me to run a thick gasket and lose my quench!
What kind of dcr would this cam have ?
Part Number 12-250-3
Engine 1955-1998 Chevrolet
262ci-400ci
8cyl.
Grind Number CS XE284H-10
Description
--------------------------------------------------------------------------------
Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.507 0.51
Duration At 0.006 Tappet Lift 284 296
--------------------------------------------------------------------------------
Valve Timing At 0.006
Open Close
Intake 36 68
Exhaust 82 34
--------------------------------------------------------------------------------
These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 240 246
Lobe Lift 0.338 0.34
Lobe Separation 110
--------------------------------------------------------------------------------
Recommended Valve Springs 986-16
What kind of dcr would this cam have ?
Part Number 12-250-3
Engine 1955-1998 Chevrolet
262ci-400ci
8cyl.
Grind Number CS XE284H-10
Description
--------------------------------------------------------------------------------
Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.507 0.51
Duration At 0.006 Tappet Lift 284 296
--------------------------------------------------------------------------------
Valve Timing At 0.006
Open Close
Intake 36 68
Exhaust 82 34
--------------------------------------------------------------------------------
These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 240 246
Lobe Lift 0.338 0.34
Lobe Separation 110
--------------------------------------------------------------------------------
Recommended Valve Springs 986-16
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
IMHO, it's Likely you'd have ample clearance w/ .550" valve lift.
Only one way to KNOW ... set it up w/ clay & a dial indicator on valve tip and measure the compressed clay's thickness w/ a caliper etc.
Get someone else to do the dcr.
Only one way to KNOW ... set it up w/ clay & a dial indicator on valve tip and measure the compressed clay's thickness w/ a caliper etc.
Get someone else to do the dcr.
Last edited by jackson; Feb 11, 2007 at 10:39 AM. Reason: rephrase
Thread Starter
Pro
Joined: Dec 2006
Posts: 665
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From: wilmington nc
ok Jackson,Thanks so much for all your help explaning quench and compression you"ve been very helpful thanks again david
Last edited by dmaaero; Feb 11, 2007 at 06:11 PM. Reason: rephrase
