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  #16 (permalink)  
Old 10-16-2012, 01:20 PM
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What do you guys think about the nostaliga cam from comp cams I listed?

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  #17 (permalink)  
Old 10-16-2012, 02:15 PM
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Thise old factory grinds belong in a museum with 8 track tape players and stromberg carbs. I hope I don't sound snotty or anything but cam science has changed a lot in the last 10 years, embrace it.
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  #18 (permalink)  
Old 10-16-2012, 03:13 PM
How fast is fast enough?
 
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[quote=hpete;1599643]
Quote:
Originally Posted by ap72 View Post
Of the cams you listed the xe274 is the best. If you insist on using that cam the Vortec heads would really bennefit from a good valve job and porting.[
A good valve job that includes 2.05 intakes, 1.6 exhausts, swept chambers and enlarged bowls
no. 1.94/1.6 valves. Using larger than that is just going to cost you, your peak flow is limited by the pushrod pinch in the runner, taking it all the way out will allow you to effectively run 2.02" valves but more than that is going in the wrong direction.
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Old 10-16-2012, 06:10 PM
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ap72 I don't agree. Although it would be better to fully port the heads along with the bigger valves, they'll still flow better even at lowlift with pocket porting and bigger valves. I would agree that 2.05's may be overkill for the application they won't hurt anything and at least here in the states 2.05's don't cost any more than 2.02's. If I stayed with 1.94's I'd be very careful who I let touch the seats.
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  #20 (permalink)  
Old 10-16-2012, 07:24 PM
How fast is fast enough?
 
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Quote:
Originally Posted by hpete View Post
ap72 I don't agree. Although it would be better to fully port the heads along with the bigger valves, they'll still flow better even at lowlift with pocket porting and bigger valves. I would agree that 2.05's may be overkill for the application they won't hurt anything and at least here in the states 2.05's don't cost any more than 2.02's. If I stayed with 1.94's I'd be very careful who I let touch the seats.
They won't flow any more and your coefficent of discharge goes to ****. bigger valves are NOT always better.
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Old 10-16-2012, 09:05 PM
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I have the extreme energy hydraulic cam. 274 in my 69 Nova SS 355 very close to your set up and it euns very well I'd go with 274 if your looking to drive often.
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Old 10-16-2012, 10:23 PM
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I have read that adding larger valves to Vortecs is bad because it decreases intake charge velocity. Also the casting is pretty thin and close to the water jacket and cutting for larger valves increases chances of a crack developing which is also a factor that needs consideration when porting Vortecs. The intake flow numbers for Vortecs are pretty awesome. They are lackluster in exhaust flow, so if you port, do the exhaust side.
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Old 10-16-2012, 11:15 PM
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how are camshaft profiles related "directly" to rear gear ratios? An engine doesnt run any different in a boat and their "gearing" is totally different?
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Old 10-17-2012, 05:35 AM
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I have a np440 gearbox laying around, do you guys that would be better then the th350?
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Old 10-17-2012, 07:29 AM
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Cam for a Vortec 355

Quote:
Originally Posted by M.Rydell View Post
Hello! This is my first post here.


I'm just woundering what cam will be the best for my engine. Car is Camaro 69 with a th350 with 3000 stall and 3,55 gears. Vortec heads 10:5.1 cr Air gap intake quickfuel 750 e85 headers
Xe274 or 12-672-4 cs nostalgia 30-30h+ or Isky 278 mega cam

thanks alot for the help!
Cheers from Sweden!
Your Vortec heads basic operating range would benifit with a cam like this. Lunati 301A3LUN - Lunati Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com The heads don't have anything left after 5500 rpms. It would also improve them with bowl blending and mild porting.
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Old 10-17-2012, 08:31 AM
How fast is fast enough?
 
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Quote:
Originally Posted by Silver Surfer View Post
I have read that adding larger valves to Vortecs is bad because it decreases intake charge velocity. Also the casting is pretty thin and close to the water jacket and cutting for larger valves increases chances of a crack developing which is also a factor that needs consideration when porting Vortecs. The intake flow numbers for Vortecs are pretty awesome. They are lackluster in exhaust flow, so if you port, do the exhaust side.
Their exhaust flow really isn't "lack luster" when compared to any other OEM castings, and the fact that they don't have a exhaust crossover is a huge plus. They're way down compared to an aftermarket head, but no bad for a stock as cast OEM head.
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  #27 (permalink)  
Old 10-17-2012, 08:34 AM
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Quote:
Originally Posted by vinniekq2 View Post
how are camshaft profiles related "directly" to rear gear ratios? An engine doesnt run any different in a boat and their "gearing" is totally different?
They aren't related directly BUT what F'bird is getting at is that with a 26-28" tire size and a 1:1 final trans ratio those rear gears and stall would help put the operating band of the engine closer to where the cam causes it to make most of its power. If you move your power band up then you need steeper gears to make your car run at that RPM.

Changing gears is not totally necessary but in most cases it enables the driver to make the best use of the new found power at the higher RPM ranges.
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  #28 (permalink)  
Old 10-17-2012, 08:48 AM
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AP72,you are correct"They aren't related directly"

most cars and trucks have multi gear transmissions,to say a car with a flat tappet hydraulic cam "needs" 4.30 or 4.56 gears?
Im trying not to correct or call out anyone,but,,,,,,,?lets think about gear choices and applications.I use 3.5 gears and my cam is 256/264@50 with valve lift over 600,is my gear choice wrong?
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  #29 (permalink)  
Old 10-17-2012, 08:42 PM
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Quote:
Originally Posted by techinspector1 View Post
Here's a checklist that I wrote and that has been improved by other members. The intake closing point of the cam must be matched to the static compression ratio as you will learn by reading the tutorial from Crane that's shown here.....
http://www.crankshaftcoalition.com/w..._compatibility
That's a good read, for beginners and others who aren't clear about the relationship between c.r. and cam selection, thanks for the link. It looks like Jon and Cobalt are with you on that wiki.
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  #30 (permalink)  
Old 10-17-2012, 09:26 PM
How fast is fast enough?
 
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Quote:
Originally Posted by vinniekq2 View Post
AP72,you are correct"They aren't related directly"

most cars and trucks have multi gear transmissions,to say a car with a flat tappet hydraulic cam "needs" 4.30 or 4.56 gears?
Im trying not to correct or call out anyone,but,,,,,,,?lets think about gear choices and applications.I use 3.5 gears and my cam is 256/264@50 with valve lift over 600,is my gear choice wrong?
It's not wrong, just a different approach. Some people will run a 700R4 or simmilar style OD trans with a steep gear (like 4.10s) so they can have great acceleration and decent cruising RPM. You're doing the same thing but with a 3 speed instead of a 4- using the first two gears for acceleration and your final gear for cruising.

Its not the best thing for a strip only car but it works fine for a car that sees street time- especially freeway time.
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