Cross

iTrader: (10)

Ok We have been running the cast numbers off my LT4 Heads and they seem to not be LT4 but LT1 supposedly.

Now I am not sure where to check the numbers but I know you could get these LT4 Hot Cam kits with the cam, heads, manifold and such from GMPP and Summit as well as other places.

Could anyone shed any light on how to confirm how these were done?

It was my understanding the LT4 Intake Manifold does not fit LT1 Heads right?

How do you confirm an LT4 Intake Manifold. Its def seems to be powder coated red before hand very well because even my blue paint does not want to stick and wants to come off for the red under it.

I have pictures of the Intake Manifold and have posted them quite a few times, no one has ever commented that it was an LT1 Manifold.

Here are the casting numbers:
10207643 or 10207843 (Hard to tell if its a 6 or an 8). This brings up LT1.

Now here are the pictures of the Heads and Intake Manifold I have:
Manifold:



Heads:





Thanks everyone.

RamAir95TA

iTrader: (2)

Take a look at this page and see if it helps.

http://www.grandsportregistry.com/lt1vslt4.htm

Cross

iTrader: (10)

Thanks but I am not sure still what too think.

Esp on my questions of the LT4 Intake Manifold fitting LT1 Heads etc. I am still looking for how to tell its an LT4 Intake Manifold

Ok I got a 12550631 on my Intake Manifold and it says 12550630 for the LT4 but the LT1 is no where close to that number either.... WTH do I have here?

RamAir95TA

iTrader: (2)

12550630 and 12550631 both seem to be LT4 manifolds.

The LT4 manifold will NOT fit LT1 heads. They will bolt up, yes, but the ports will not match. Why don't you bolt one of the heads to the manifold and see if they line up?

Cross

iTrader: (10)

because i ran the motor this way for over 1500 miles.. guess i will bolt it up and see.

96capricemgr

iTrader: (1)

The LT4 manifold is internally the same as the late LT1 manifolds. The problem is actually the extra material above the runners can interfere with the valve cover rail on LT1 heads. Take the interfereing material off the LT4 manifold and it is an LT1 manifold.


Here is a pic GIZMO posted some time ago to try and dispell all the myths.
http://i85.photobucket.com/albums/k5...1/DCP_1456.jpg

The head casting number seems to be LT1.

za355tx

iTrader: (108)

The ports CAN be matched to work but not alot of people do it. I just so happen to have a set of LT1 heads ported and matched for the LT4 manifold I have (laying around). They have been run with no probs. Lloyd also says you can do it. There is barely enough material on the LT1 head to open the ports to be tall enough to match but there is enough. And if I remember correctly one of the casting numbers on the manifold is the casting number from cars that came equipped with an LT4. The other is the manifold you used to be able to buy from GMPP. I don't remember which mine says however.

In your case and by looking at those heads...the ports do look pretty tall, like maybe they were at one time ported to match the LT4 manifold.

96capricemgr

iTrader: (1)

How is it that 45 minutes after I post the info and a PICTURE someone still manages to repeat this BAD info that the manifold ports are taller??

Yet you guys doubt me when I say most posters are imbeciles?

za355tx

iTrader: (108)

Edited

96capricemgr

iTrader: (1)

The head ports are taller, the intake ports are not.
Again see the picture I linked.

shbox

Actually, they don't bolt up without interference with the valve cover gasket rail on the LT1 head. The A and B head intake cross section pics in the very link you posted clearly shows that.

fergymoto

iTrader: (129)

Dwayne, quit being mean to everyone, and please stop spreading good info that some people don't want to believe

za355tx

iTrader: (108)

Edited.

SS RRR

iTrader: (2)

At least on my LT4 cylinder heads I pop a valve cover off and have a "LT-4" ID stamped next to a valve spring...

96capricemgr

iTrader: (1)

https://ls1tech.com/forums/10425864-post13.html

https://ls1tech.com/forums/9311130-post3.html

https://ls1tech.com/forums/10086996-post11.html

https://ls1tech.com/forums/7469406-post13.html

https://ls1tech.com/forums/4023282-post26.html

I just focused on posts from those two individuals because I specifically remembered them having posted the same info repeatedly.

Now just imagine what else you are wrong about but refuse to see??

za355tx

iTrader: (108)

Well then in that case I would have to say I am wrong. I'll be the first one to admit when I made a mistake. I'll edit my posts.

However on the other hand...I don't see why it's necessary to belittle people by calling them imbeciles and they saying you wonder what else I am wrong about that I refuse to see...Just being a rude, arrogant person and that's not needed. Can you answer to why you do that to people and why you act that way? You make it seem like you have never been wrong in your life...The way you treat people is wrong.

myltwon

iTrader: (1)

because he doesn't realize people don't INTENTIONALLY give out bad info, there's alot of internet myths floating around about things and many people have bought into them like the majority have as well. there are more constructive ways for him to convey his message but I guess being a ***** better suites his personality

the guy has alot of great info but it often comes with a spoon-full of douchebag

za355tx

iTrader: (108)

I agree...I've seen alot of good info come from him but I just don't see why he has to say it the way he does. Oh well I guess that's just the way he is. I would never intentially give someone wrong info...I honestly thought that's the way it was but I was proven wrong. That's ok if I don't have something right I'd like to know. Everyone makes mistakes.

myltwon

iTrader: (1)

we are all here to help each other learn. when you react with hostility it makes people less likely to offer advice for fear of verbal retribution if infact that what they post, even though they thought it was correct, turned out to be false.

xx_ED_xx

iTrader: (17)

LOL I like that spoon full of douchebag