|
Num Posts
Sort Order
|
|
Posted: 08/23/08 09:24 PM
|
|
Details 327 standard Vortec heads 4-speed 29" tire 3.73 gear 9.1:1 L-79 cam 55 210- probably 3400lbs. .040 quench
Looking to install: Comp Xtreme Solid .230/.236 488/510 Edlebrock RPM air gap
(I have modified the head for larger springs and are setup to accept .525 lift)
Concerns: compression too low to run cam. Do I need go deaper in the gear?
Your turn- is my 'concern' concerning you too?
|
JW454
Enthusiast
| Posts: 289
| Joined: 07/08
Posted: 08/24/08 05:00 AM
|
|
Duration is a bit long for a 9.1:1 comp ratio. Makes for a soggy bottom end. Look for an intake closing point around 48-54deg. ABDC, and a dur.@.050 of 215-225, would work well on the street. When I do the math, the cam you mentioned would need at least 10.5:1 comp ratio to work well. I know it's expensive but a roller cam will give you all the lift you want, and keep dur.@.050 in check. Are you planning on spinning high rpm's that you would use a mechanical cam?
|
JW454
Enthusiast
| Posts: 289
| Joined: 07/08
Posted: 08/24/08 05:10 AM
|
|
I noticed in another post you mentioned having the correct quench. How right you are, as this important factor is usually overlooked. .038-.040 is prime. Unless a block has been zero-decked, you would need the steel shim gasket to keep quench correct.
|
|
|
|
Posted: 08/25/08 11:50 AM
|
|
JW... thanks for the reply... I thought the 230 would be too big... I do have another question to bounce off of you...
I've never CC'd a stock Chevrolet piston, do you have any idea what a 327 GM std piston would CC at?
My other figures look like this .025 deck height, 64cc chambers, .015 steel Fel Pro gasket 4.060 gasket bore, so I assumed around 9.1-9.2:1... If you knew the cc's of a stock 4 eye brow piston, I would be for sure how much compression I'm at. I was figuring 7-8cc's.
Yes, it's kind of a hot street setup... turn about 6,000-6,200.
|
JW454
Enthusiast
| Posts: 289
| Joined: 07/08
Posted: 08/27/08 09:23 AM
|
|
I do not know the piston volume. I would have to guess that -7, -8cc's would be in the ball park. Spinning those high rpm's will require at least 230-236dur.@.050 and some good valve springs. If your going to spin it that high, maybe low and mid range torque is not a concern.
|
GibTG
Moderator
| Posts: 1358
| Joined: 10/03
Posted: 08/27/08 10:02 AM
|
|
No need to worry about the cam he mentioned because it does not exist. There is no solid roller Comp Cam with 230° @.050 with only .488" lift.
|
|
Posted: 08/28/08 03:57 AM
|
|
I think he is looking at the Xtreme Energy 268 solid. It is a flat tappet not a roller.
|
GibTG
Moderator
| Posts: 1358
| Joined: 10/03
Posted: 08/28/08 08:28 PM
|
|
[deleted at the request of the author]
|