Seal

whats the cc on stock heads?

FryedClutch

i belive the stock combustion chambers are between 54 and 56cc

ejfagala

This link will have the cc for all LT based heads and much more. You should find your answer here

http://www.automotiverebuilder.com/ar/ar99928.htm

arnie

Maybe half blind, so where on the site would that be? What I do see, is misleading.

simple

170cc intake runners
~56ish (some say 54,some say 58) cc's in the combustion chamber (big debate a while back about what the true number was for a stock head, search it)

n2ceptor

According to "How to rebuild a LT1/LT4 engine book" ; LT1--58cc LT4--54.4cc

ejfagala

Ok they only listed the cc for the LT4 54cc but the LT1 is only .4cc bigger

What is mis leading?

Here is some more info on the diferences between the Lt1 heads and the LT4s

http://www.malcams.com/legacy/misc/LT4.htm

Seal

yeah just read that while i was taking a crap

arnie

Apparently, you don't know. So which is it? Is the LT4 chamber larger, or smaller? It is helpful that people study the links that they reference, so they know what they are referencing. Wouldn't you agree? First you provide a link that is inaccurate, then confuse the issue, with a link that is contradictory.

This publication is comparing apples to oranges. Because of that, that publication is also inaccurate.

If one would do a search, they'd find numerous posts by 'arnie' that would state what the facts are, providing the threads are still in the archives. The print specs for the LT1 is 54.0. The print spec for the LT4 is 54.4. The actual specs for the LT4 heads, as they come out of the machining center is more like 1 1/2 to 2 cc larger than print. The actual LT1 chambers can vary from spec (or slighter smaller) to a full cc larger on earlier heads, and (according to some) upwards of 3 larger on later heads, although I personally have not cc'd chambers that large. Heads I come in contact with, I actually cc (accurately) myself, so info presented, is personal experience, not internet/forum hearsay.

The archives, although it can take a little effort, can be very revealing.

ejfagala

There is some conterversy over the cc for the LT1 but in all cases it is a larger chamber then the LT4. I have never had a stock set of LT1 heads checked so I have to depend on what I have found via reading. In any case the statment form the first web site is acurate the LT4 heads did use smaller 54cc chambers (54.4cc-vs54.8)

"HEADS - The heads had smaller 54cc chambers that gave the LT4 a 10.8 to 1 compression ratio. The intake ports were raised 0.100", too. The LT4 used larger intake and exhaust valves (2.00" x 1.55" ). The intake stems were hollow to reduce weight and the exhaust stem was sodium-filled to improve the LT1 heads are 54.8 cc, the onlt statment that is "misleading is that the compretion was also increased through the resizing of the valve pockets in the LT4 pistons.
heat transfer. The valve springs were made of oval wire to prevent coil bind with the higher valve lift and fitted with lightweight retainers to help the engine rev to its 6,300 rpm redline."

The second article also references the LT4 chambers but it does not controdict the first web site if the LT1 heads are .4cc larger then both are correct. The only misleading statment is the first web site does not address the fact that the changed piston also had an impact on the comp.
"Combustion chambers are almost identical (there was a negligible .4cc difference) Volume for LT4 Combustion chambers are 54.4cc's."

arnie

I stand behind the specs I posted, both print and actual. They obviously do not jive with what was posted just prior to this post. There can be some disagreement/variance over what chambers actually measure, but not in regards to print specs.

BlueCamaroZ28

Is the LT1 iron head 64cc or 58cc?.

ejfagala

I am just going off the information at hand and if you have tested the heads then I stand corrected. There is a lot of confusion about the cc of the LT1 heads both published and tested. I find it interesting that there is such a large disparity between various authors. I have seen stock GM LT1 heads published as 58cc in print in several different places including people who are selling heads and pistons. I am not justifying any of these specs just using them as a point of reference. Take a look at GM parts direct http://www.gmpartsdirect.com/perform...CATID=856.html and notice that all references to the LT1 use the 58cc and for the LT4 they use the 54.4 and they are a GM parts retailer, so you can see where the confusion comes in when you state that the heads are 54cc’s. I can not verify either source so I am just at a loss.

arnie

I understrand what you are stating, and understand your dilemna. That is why I am, and have numerous times in the past, taken the time to set record/facts clear. There is too much misinformation on the net, as it is. Just because info is posted on an otherwise reputable site, does not guarantee it's accuracy. Unaware, ignorant, or sloppy web hosts post info without clarification, and without taking the time to verify it's accuracy, with viewers accepting it as gospel, especially if they see it more than once. It is human nature to accept info, at face value, without any research of it's accuracy, initially, but reject followup facts, while refusing to do any research to verify, cuz they (the facts) are contradictory, to the initial exposure/info. It doesn't matter, whether it is info regarding government, health, or automotive issues. The first in, and/or the more repetitive, is the more influential. Human nature.

Much closer to 64 cc. It's a different chamber shape (more open), btw. The actual print spec, is unclear to me.