Okay the Intake Centerline (ICL) is 107.8

 

Well you see, Jordon has been telling me that the heads are stock LT4 ccs, so that is why I assumed that even though what he has done, they are still 54.4cc
I sent Jordon an email today at work, and I am looking forward to what he thinks. I totally trust Jordon, and I will do whatever he thinks we should do.

 

okay, you have 4 degrees advance then. LSA-ICL.

Do you have the .006 duration numbers?

 

As in the head flow numbers?

 

no, cam duration. Card should have duration at .006" lift and .050 tappet lift.

 

Hey Matt.. The .006 duration would also be listed under an "advertised" heading. I'd imagine it to be in the 30X-31X area... Like a "CC306" is 230/244 @ .050.. Advertised #'s are like a 292/306 I believe. <- Just for comparison's sake.

 

The only thing I got on the entire page from Cam Motion is the duration at .05, which is Intake = 245.7 Exhaust = 251.1

 

Does it reference the intake lobe as x-2461?

That lobe has an advertised duration of 300.
This puts your IVC at 77.8 degrees ABDC

Assuming your static was calculated correctly at 12.2:1 (which i doubt because i doubt they are 54.4 cc chambers)
Your dynamic compression would be a very safe 8.64:1 and i would actually recommend you mill the heads down some more.

Check with jorden on the chamber size though. Discuss compression with him since you trust him, he should have some input.

-brent

 

The only thing even close is Intake lobe lift = .40917 in. and intake lobe area= 32.99 in * DEG

It also lists lobe size bc/ht IN: .975 and EX: 1.015

 

Whoa, i was looking at hydraulic lobes. Is that a solid roller? Yes i see it is, my bad.

If so then r-2481 and the adv duration is only 281 and your compression will be too much *if* those static numbers where correct.

http://www.cammotion.com/Portals/fee...a1a/Binder.pdf

Edit* Okay, I'm just ran that cam lobe with an IVC of 68.3 with both assumed static compressions.
12.2:1 -> 9.44 Dyn
11.8:1 -> 9.14 Dynamic (still a lil too high for pump gas)

My advice, talk to jordan.

g'night
-brent

 

I take it you have checked LT4 heads yourself? As worded that statement is not entirely accurate! It is no wonder there is so much misinformation floatin' around. Helpful people just guessing.
That is cuz so few know what they are talking about.
That is an incomplete answer. So as such, it is at least misleading.

Doing a search is a good idea. To save you some trouble, search under 'Arnie'. Have no idea how many of those threads have been deleted from archive due to date issue, but those that remain have one thing in common, consistency. The info is based on actual checking, not guessing. This goes for the LT1 as well as LT4 heads. From now on, when someone submits an answer to this question, it may be a good idea, to inquire whether they actually checked the head they are referring to, or just echoing what someone else posted elsewhere. It will help stem some of the misinformation being posted.

 

Arnie,

I definitly agree with everything you said about the spread of shaky information, but to be fair to chevyguy, he also did post the above statement immediately after the chamber sizes he listed. And as i previously stated I do agree with chevyguy that the builder should just verify it instead of guessing, which is in a sense what you're saying as well.

-brent

TexasTA, did you talk to Mr. Musser?

 

Arnie, i did a search and in multiple threads you posted having measured stock LT1 chambers as being right around 54cc (+/- 3-4 tenths you say), so i dont understand what your problem is with the information that was posted?

i dont currently have any un-molested LT1 castings laying around, but i do have a set of untouched LT4 heads laying in the basement that i will measure when i get home from work just for the hell of it.

 

Damn Arnie didn't mean to step on your toes so hard...but maybe you should go to all these sites and inform them how their data is wrong as well with these UNTOUCHED LT heads.

I do agree that the porter had better cc a head after working on the chamber or doing any valve work.

LT4 head data

LT4 head data

LT4 head data

head data

 

To be fair, I can read. The content of my previous post stands.
The figure above still stands, as well as figures themselves, in your previous post, being accurate. Your account of the figures is good, but you left out important details. Thus, as posted, opens the door to a misunderstanding. As such, I considered the figures taken out of context. Without 'qualifying', or explaining the figures in more detail, as I took the time to do, in numerous previous posts, both here and in 'Advanced', those that read the post, will leave with a distorted viewpoint. In my previous posts, I used figures... 54.0, 54.4, another but different 54.0, as well as a range of figures, all in the same post. Why? That was necessary to 'paint' a true picture, and allow the reader to walk away with a clear understanding of the figures presented. Your response didn't present those (accurate) figures in the same 'lite' or context as I did. As such, although accurate, those figures may not (depending on the head) represent figures people discover for themselves, if they were to check their heads.
You aren't, intensity is mute. The problem with the misinformation I am referring to, is two fold. Too many sites, (both info and retail sales) including ones you linked, spread misinformation and/or inaccurate info, because they do not qualify those figures. Intentional or not, it's also a mute point. Second, well intentioned people post/spread this misinfo with no personal verification of any kind, whether it is referenced from a website or another thread/post. Because it is on any given website, it is unquestioned regarding it's accuracy. People blindly believe info obtained from the net, is automatically fact.

Bottom line guys? After reading my previous posts, those that check both LT1/4 heads will know what to expect when they check, and when #s don't jive with figures displayed on websites, they'll know why. For that reason, I recommend my archved posts for you guys. Although Chevyguy appears familiar with my archived posts, I believe he just needs to refresh himself with the details. My posts were not intended to discount or dismiss your TRUE intention(s) above.