How does my 355 setup sound?
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Joined: May 2004
Posts: 305
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From: Texas
Car: 1991 Z28
Engine: 350
Transmission: 700R4
How does my 355 setup sound?
-forged crank, h beam rods and SRP flattop pistons, balanced
-plasma moly file fit rings
-all arp bolts
-4 bolt sbc 350 truck block
-clevite 77 bearings
-high volume oil pump
-Dart pro 200cc aluminum heads with minor port and polish work, and gasket matched
-Accel superrram with 1000 cfm throttle body
-double roller timing chain
-Comp Cams CS XR269HR-12 , Duration 218 224, Lift .495 .503, Lope Sep 112
Plan on running my N.O.S. plate along with a fogger setup later.
Just wanted to get some opinions on my cam choice and any last minute changes that should be made.
-plasma moly file fit rings
-all arp bolts
-4 bolt sbc 350 truck block
-clevite 77 bearings
-high volume oil pump
-Dart pro 200cc aluminum heads with minor port and polish work, and gasket matched
-Accel superrram with 1000 cfm throttle body
-double roller timing chain
-Comp Cams CS XR269HR-12 , Duration 218 224, Lift .495 .503, Lope Sep 112
Plan on running my N.O.S. plate along with a fogger setup later.
Just wanted to get some opinions on my cam choice and any last minute changes that should be made.
Thread Starter
Member
Joined: May 2004
Posts: 305
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From: Texas
Car: 1991 Z28
Engine: 350
Transmission: 700R4
Well i originally went Twin Turbo BBS designs headers and turbos and in the process i had a 355 built at my machine shop with low compression pistons, all forged. So when i changed my entire setup back to N/A it would be far easier to swap pistons than buy a stroker kit and then have my block machined for a longer stroke.
But since my orignal blower setup was balanced i decided to just go ahead and buy another complete rotating assy already balanced with the higher compression pistons that i needed. So if i could only go back in time.... i would have went stroker and then i would not have a sh$%load of extra parts laying around. But my plate nos (150 shot) combined with my fogger (up to 300 shot if i want to grenade my motor) will make up for the lack of cubic inches
Also i did not mention that i will be running 10.3 c/r.
But since my orignal blower setup was balanced i decided to just go ahead and buy another complete rotating assy already balanced with the higher compression pistons that i needed. So if i could only go back in time.... i would have went stroker and then i would not have a sh$%load of extra parts laying around. But my plate nos (150 shot) combined with my fogger (up to 300 shot if i want to grenade my motor) will make up for the lack of cubic inches
Also i did not mention that i will be running 10.3 c/r.
Thread Starter
Member
Joined: May 2004
Posts: 305
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From: Texas
Car: 1991 Z28
Engine: 350
Transmission: 700R4
I thought it was pretty good cam coming from stock Lift .413 .428 Dur 202 207 and i was told it works well with the superram.
Well what would you go with ? because i have not put it in yet, waiting on a degree wheel
Well what would you go with ? because i have not put it in yet, waiting on a degree wheel
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Joined: Sep 2003
Posts: 6,859
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Seeing as you will be running NOS that changes things. I would call the cam manufacturors for their recomendations.
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Joined: Jun 2005
Posts: 106
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From: Fort Hood Texas
Car: 88 IROC
Engine: 305 tpi
Transmission: 5 speed
I would ditch the high volume oil pump. I would use the stealthram instead of the superram. That 1000cfm throttle body is to big for what you have I would use the 52mm. Heads are ok however I am totally sold on the AFR 195s. The cam is way to small my 305 has a bigger cam and it drives fine. I would use at least 222/230 509/522 112 from crane. Just my two cents.
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Joined: Sep 2003
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Let's do some math on what size cam you need. Let's start off with a 6000RPM goal.
CFM requirements. 355x6000/3456=616CFM
Divide by 8 cylinders equals 77CFM per cylinder.
Lets say your heads flow 260CFM with intake. Thats alot.
X= 77/260 X=.296
The cams need .296 of 720 degrees of duration which equals about 213 degrees. Sounds like your selection of 218 degrees is a good one with some wiggle room. If your heads can handle it I would look into the Comp Cams XFI 268.
What are the exact intake and exhaust flows for the head say at .500 and .600 lift?
CFM requirements. 355x6000/3456=616CFM
Divide by 8 cylinders equals 77CFM per cylinder.
Lets say your heads flow 260CFM with intake. Thats alot.
X= 77/260 X=.296
The cams need .296 of 720 degrees of duration which equals about 213 degrees. Sounds like your selection of 218 degrees is a good one with some wiggle room. If your heads can handle it I would look into the Comp Cams XFI 268.
What are the exact intake and exhaust flows for the head say at .500 and .600 lift?
Last edited by 1989GTATransAm; Dec 11, 2005 at 01:00 PM.
Thread Starter
Member
Joined: May 2004
Posts: 305
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From: Texas
Car: 1991 Z28
Engine: 350
Transmission: 700R4
I called comp cams and thats why i bought the one i did, they recomended it. My other choice was a comp 280XFI HR13 Lift .576 .571 Dur 230 236 Lobe sep 113 that my machine shop told me to get.
Thread Starter
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Joined: May 2004
Posts: 305
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From: Texas
Car: 1991 Z28
Engine: 350
Transmission: 700R4
Called comp cams again today and they told me if i wanted a bigger cam to go with their 280XFI HR13 Dur 230 236 Lift .576 .570 Lobe sep 113
or CS XR276HR-12 Dur 224 230 Lift .503 .510 Lobe sep 112
Im trying to match a cam that will run with a stock converter untill i have the money to upgrade. Im going to order a new cam tomarrow for sure, so any help narrowing the choices down would be great.
Also the heads flow 264cfm intake @.500 and 180 exhaust @.600, from darts website.
or CS XR276HR-12 Dur 224 230 Lift .503 .510 Lobe sep 112
Im trying to match a cam that will run with a stock converter untill i have the money to upgrade. Im going to order a new cam tomarrow for sure, so any help narrowing the choices down would be great.
Also the heads flow 264cfm intake @.500 and 180 exhaust @.600, from darts website.
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iTrader: (3)
Joined: Sep 2003
Posts: 6,859
Likes: 14
From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
More math. 180/264 equals 68% on the I/E flow ratio. You will definitely need a split cam. You can custom order an XFI cam with a 224 degree on the intake. Lobe number is 3015. The exhaust side lobe 3038 which is 230 degrees. I would stick with the 113 degree LSA for fuel injection. Double check all this with Comp Cams.
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