Well, you answered the 1st part of my question very well, and thank you. My wording was a bit vague on the second part though. I didn't exactly mean how much flow to support that cam but what heads will support that cam, in other words will the stock springs handle that lift?

 

Brokeback Mountain is a movie about two gay cowboys. Didn't do that well at the box office here in Oklahoma.

 

And I suppose you've had at least one course in Thermodynamics to support the above statement? Heat transfer from the exhaust to the exterior (via conduction and then convection) will occur. The ideal gas law shows that a decrease in temperature will result in a decrease in the product of P and V, within the confines of the control volume used for the analysis. How much P or V or both decrease depends on entropy. Explain the change in entropy where expansion "requires less energy" (your words).

I think you already accomplished that. This would be your 2nd time.

I didn't know that people from the audio design world know anything about the kinetic theory of gases. I also didn't know that lighter molecules don't have the force that heavier molecules had. I wonder how this would change the mixture model of gases at thermal equilibrium where the molecules would have had ample time to spread the kinetic energy around. And I didn't know, furthermore, that dust is important in any of these discussions.

There are ample sources on the web that explain thermodynamics as applied to gases, and going past those fundamentals, there's open courseware on engine technology. I won't do your homework for you in finding them, but I do suggest you find them and read them.

 

I was curious about that too.

 

Yeah, and I am trying to figure out what I have to do with that. I assume you are just trying to call me gay, I can't figure out why you felt the need to insult me in your reply.

 

I don't think he meant anything personal about it. Just that we are old as dirt members and he was jokingly trying to make a point. But then again I don't know.

 

An LT1 cam is pushing the limits of the stock springs, even if they can handle the lift I doubt that they'd have the spring pressure to control the valves at higher rpms. Plus, your old springs will be fatigued from years of use. Springs are relatively cheap so you'd be MUCH better off getting some new ones ...with higher pressures and rate than the originals (which are inadequate). Go for something with a seat pressure of around 85-100 lbs (@ 1.700") and open pressure of 250-310 lbs (@ ~1.200").

 

IIRC, the specs on the springs I use are 110 @ 1.700" and 290 @ 1.200" with .510 max lift. I am putting LT4 springs/retainers on everything I am building now.

 

I am also running the LT4 springs. If you are going to all the trouble of cam swap, take the extra few minutes, and put in new valve springs.

 

Cool thanks once again for the input guys.

Another thing I was wondering was about was seanof30306 mentioned something about 64cc's dropping my compression too low. I think the heads I was planning on using are 64cc heads too. What would they need to be milled to to maintain around 9.5:1 or maybe up it to 10?

 

I agree with this statement. I don't believe Sean meant anything derogative to either. Just stating someone who is very new starting arguments in almost every thread involved and comes in here debating with members with experience not bullsh!ting.

Also thanks to kdrolt.

Back to reality and the poor guys thread.


KniteWulfe I have had the standard GM Vortecs installed on my 305 for 5 years. No milling. I think the compression loss in overrated. Who knows what the Vortecs actually cc at without checking themselves as I read early on that GM stated that most of the castings were around 61cc. So take that for what it's worth but they run pretty good as is. I bought them for a 350 and they will end up back on a 350. I would not mill them.

My 2cents.

 

Hey who you callin poor?

Well I wasnt referring to the vortecs, my friend has some heads from his truck that I will probably use and he thinks they might be 416s or 601s. He still has to check the casting. He said he was pretty sure they were 64cc though.

 

416s have the same "open" style combustion chamber as the 081s and 187s. They're about 58cc. 601s have a much smaller "closed" style combustion chamber because they were originally cast for the 267 engines of the 1970s ...most people say they're 53cc. I haven't cc'ed them myself, but I have a set on my table next to 58cc 187s and I guarantee that they have significantly smaller combustion chambers ...53cc actually seems large for them.

 

Dude, I was just kidding. No offense intended. Please accept my apology. What DVDs you watch over and over and over and over and over and over are totally your business.

 

I helped a buddy cc a set of SDPC Vortecs, they came in at 63cc.

The CHP Mission 305 Vortecs were milled .060, which is .030 more than I've been told they should be milled by a head rebuilder I've done a lot of business with and trust. He said they're prone to cracking as it is, and milling them makes them even more so.

The Mission 305 article listed the compression at anywhere from 9.5:1 to 10.5:1 after the milled Vortecs were installed (with the thinnest head gasket available). They were attempting to calculate the compression mathmatically, though, they never actually measured it; I'd be a little leery of their results. This is the same guy who RAVED about how well the car drove without any chip tuning until someone from here called him out on it. In the next article, he admitted it actually drove like a pig until they got the new chip.

 

Back to the heads. You would also need to watch for chamber size. You dont want to lose compression from to big of chambers. You will need to stay around the 58cc to keep your compression up.

 

If my memory serves me correctly I think the general rule of thumb is 3% power for every point of compression. So droping a half a point is around 4.5HP on a 300 HP motor......totally not worth worrying about. With gas prices now 87 octane looks very apetizing.

 

Ok, so then how many CC's make up a point of compression?
I agree about the 87 octane. That seems like alot less than I expected, but the desktop dyno gave about that result too. I could probably figure that out with the software but I'm still learning how to use it.

 

My thoughts exactly............and I have run only 87 for years.

 

[quote=DrummerDad]I was a stock L03 auto, running 2.73s, at 1400+ feet. 16.8 is actually good. At sea level it would be a little better. Its not uncommon for LS1 powered f-bodies to run 14.0s here. With a little work a few have broke into the 13s, with the 6 speed.

Not saying thats bad, but ive seen Stock LS1 powered f-bodies running high 13s very regularly at my track. Im at sea level too.

 

[QUOTE=Rossi]My track is 600' above sea level where my TBI 350 will run 16.08s @ 86ish.

 

[QUOTE=Rossi]
Thats what I was saying. We are 1475 feet above sea level. An LS1, 6-speed here on average, runs about a 14.0, maybe a 13.8, if theyre lucky. At sea level, it could be as good as a 13.5.